(Topic ID: 218176)

Roadshow eyelids up coil stuck on


By SPARKY70

1 year ago



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  • Latest reply 6 months ago by german-pinball
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Fuse Roadshow (resized).JPG
C3C0A8B6-83A0-4954-A394-2C9EF35F2F78 (resized).jpeg
schematics q54 zoomed (resized).png
2019-01-13 00_03_41-TEDWIRING (resized).jpg
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sol11 short (resized).jpg
99E3AB72-823D-4155-81EF-2A9A409EED96 (resized).jpeg
FA5F8F22-7118-4305-9E1E-845EC4A37C51 (resized).jpeg
test sol11 (resized).jpg
8529E70F-949F-40DF-9CF9-7140F8FEFC19 (resized).jpeg
97B54598-826D-4D1A-B915-DC921D677B13 (resized).jpeg
PDB Driver (resized).png
C1ADCA7C-22D2-441D-90B7-514DB79EAFBA (resized).jpeg

There are 58 posts in this topic. You are on page 1 of 2.
#1 1 year ago

This topic was started as a private message. Below is the start of private message.

Hi Grumpy, after working with you on my high speed, i was hoping you could help me gain some insight with another issue i wanted to take care of.

Im not sure if youhave the time, but just incase, here is whats going on:

A few months ago, i bought a WPC-S ROADSHOW.

1 of the solenoids #11 “TEDS EYELIDS UP” was not working.

I disassembled ted, the lids up coil was bad so i replaced the coil for the eyelids.

I checked its transistor Q54. I buzzed out the tab to ground, and it buzzed as bad.
I also tested its legs, which also tested bad.

I replaced Q54 reinstalled the board, and it is still energizing SOL 11 when it shouldnt.

Teds head has a plug which i unplugged so i dont burn out the new coil.

I just tested the pre driver Q53 and it seems to be good.

According to my research, there is a chip ttl 74LS374 that could possibly be bad.

I read that i can put my dmm in diode test with the red lead on the ground leg, and the black on the others. They should test .4-.6 except for the power leg.

I was hoping you could help me figure out which chip it is, and which leg is the power leg.

I have a pic of the pinouts for the chip but cant seem to post it in this message.

It looks like 10 is ground, 1 is input control or OE, 11 is clock and 20 is Vcc.

Also i was wondering if there another way to check to see whats causing the issue, or if i should use my new logic probe somehow. Thanks again for your time. Sparky

**************************Grumpy replied**************************

Hey Sparky, hows things going with you. Here is a tech tip I learned the hard way. Any time you have a shorted driver, you always replace the shorted driver, predriver and diode and also test the coil for the correct ohms. This only cost you an additional .60 cents in parts and will save you lots of time and frustration.

Now on to your problem, U-4 is the LS374 that needs to be tested.

Pin 5 of U-4 turns on Q-53 by going high.

So use your logic probe and see if pin 5 is stuck high, if it is then you will need to replace U-4.

If it is low then you have a broken trace between pin5 and the base of Q-53.
It can also be a bad solder joint on Q-53 or pin 5 of U-4 causing it to seem like a broken trace.

The last thing is if pin 5 is low, then Q-53 can be bad even tho it tested ok.

D-22 should also be replaced as it is the diode for the shorted coil you changed.

#2 1 year ago

Hi grumpy, things are ok here for the most part, how about you?
thanks for taking the time again to help out.

I just attatched my logic probe to TP2 5v & TP5 ground.
I tested U4 pin 5 as you suggested, and it is hi.
However, i tested pins 2-9 and 12-19 they are also hi. The legs marked with a “D” get a beeping hi tone, which seems normal.

The rest of my solenoids work correctly, so
I also checked all U3 pins and It tests exactly the same as U4.
It seems like hi is normal for pin 5??

I tested during coil 11 test mode, and game over mode since it is always locked on. Same results for both.

Which mode should i be in while testing? Thanks. Sparky
C1ADCA7C-22D2-441D-90B7-514DB79EAFBA (resized).jpeg

#3 1 year ago

is it just one coil locking up?
1.coil
2.diodes on coil(if there are any)
3.pre drive transistor-drives that coil
4.main transistor-drives that coil
change them all at once

#4 1 year ago

Hi cyclone, only that coil has a problem. The rest of the game works flawlessly.

1. Coil is new.
2. No diodes on that tiny coil
3. Pre driver transistor tested good but i didnt replace
4. Main transistor is new.

#5 1 year ago

So when the game is on, is the transistor getting a high signal? If so, then your problem is behind that transistor. If not, the problem is that transistor or forward.

#6 1 year ago
Quoted from SPARKY70:

Pin 5 of U-4 turns on Q-53 by going high.

This is incorrect, Q53 (2N5401) is a PNP transistor, it requires a low on its base to turn on.

Quoted from SPARKY70:

The rest of my solenoids work correctly, so I also checked all U3 pins and It tests exactly the same as U4. It seems like hi is normal for pin 5??

Yes, a high output of the 47LS274 is normal for all de-energized coils.

The following diagram is drawn in an energized state with green highlights representing low signals, and red representing high signal levels. Also keep in mind that regardless of any circuit operation, if you have a path to ground at pin 4 of J129, your coil will energize.
PDB Driver (resized).png

#7 1 year ago

Thank you cadillac, and pin guy for your responses.

Pin guy, thank you for taking the extra time to highlight the diagram for my problem.

I am new to a logic probe, but can follow directions very well.

So i am still taking baby steps.

According to what you stated, i believe my chip should be ok.

Can you please tell me which leg to test for the lo coming into the Q53 pre driver, and which leg to test for the hi coming out? Is it safe to test all 3?

You say base should be lo, so i believe i should get lo at the middle.

Also which legs should be hi/lo on the Q54 driver?

I am guessing that i could put my probe on J127 &129 to check if it is lo or hi if i am safe to do so.

Can i screw anything up with the logic probe?

Thanks. Sparky
97B54598-826D-4D1A-B915-DC921D677B13 (resized).jpeg

8529E70F-949F-40DF-9CF9-7140F8FEFC19 (resized).jpeg
#8 1 year ago
Quoted from Pin_Guy:

Q53 (2N5401) is a PNP transistor, it requires a low on its base to turn on.

pin_guy is correct. I was going from memory and thinking it was a NPN. This is what happens when you get senile, Sorry about that.

Quoted from SPARKY70:

Also which legs should be hi/lo on the Q54 driver?

The base (pin 1) will low when off and high when turned on.

Quoted from SPARKY70:

Can you please tell me which leg to test for the lo coming into the Q53 pre driver, and which leg to test for the hi coming out? Is it safe to test all 3?

The base (pin 2) is the lead that turns it on and off, high off low on.
The collector (pin 3) is the output the turns on the driver (TIP 102). A high on the collector means the transistor is conducting or a on state which will turn on the driver transistor. The emitter (pin1) will just have 5 volts on it all the time.
It is safe to test all 3 for the predriver, the collector of the TIP102 will have high voltage on it and should not be tested with a logic probe. It can be tested with your voltmeter.

Quoted from SPARKY70:

I am guessing that i could put my probe on J127 &129 to check if it is lo or hi if i am safe to do so.

These can have high voltage on them so they should be checked with your voltmeter.

You diode tested the predriver and it tested good but is most likely bad causing the driver to stay on. The best testing is done with the power on with the logic probe, in attract mode the base of Q-53 should be high and the collector should be low. If the base is high and the collector is high the then Q-53 is bad. If the predriver tests good then you may have gotten a bad TIP102, it happens.

#9 1 year ago

Sparky,

While probing around on this board its always a good idea to have your high voltage removed; you should be able to accomplish this by leaving your coin door open.

Quoted from GRUMPY:

It is safe to test all 3 for the predriver, the collector of the TIP102 will have high voltage on it and should not be tested with a logic probe. It can be tested with your voltmeter.

The best way to check the collector on Darlington transistors (TIP102) is you check the metal tab; the metal tab on this type of transistor package is always tied to the center leg, which in this case if the collector. Don't be surprised if you have no voltage here since a previous post indicated your have the coil disconnected, having this disconnected will remove the +50V from the transistor as this voltage comes from the coil, not the PDB.

#10 1 year ago

Hi Grumpy, thats ok, im not sure if im going senile too, but i definately think im losing my mind.

Thanks for the added info.

And pinguy, thanks for the coin door tip.

During game over mode,
Pre driver Q53 tests as follows.
Pin 2. Hi
Pin 3. Lo

I get the same results testing other non issue pre drivers, in addition to what grumpy said, i think the predriver is good.

And Q54 as follows
Pin 1. Lo
Same as other good tip 102’s

Pin 2. Untested at this time.
Dmm set to DC?
Red lead on Q54 center or metal tab.?
Black lead on braid?
Coin door closed?
Reconnect coil 11?

Just trying to be extra careful. Thanks all Sparky

#11 1 year ago

It does sound like the predriver is working correctly. Since you have the coil disconnected you should be able to use your DMM and check the resistance of from ground to the collector (pin 2 or the metal tab) of the driver. In attract mode the resistance should be @ .900 meg ohms or higher. A low resistance will indicate a shorted Tip. You may have just gotten a bad one. Always good to test new parts first before installing, but still not 100 guarantee.

#12 1 year ago

Ok grumpy, so it seems the Ttl chip is good, and pre driver is good.

I actually gave the tip 102 a test before installing, but i guess it could still be bad.

Is there a possibility that my soldering wasnt sufficient, or does that not apply here..?
i read something about the center leg needing to make contact on the component side, and if not, the coil will fire once, then blow the tip 102. Mine has fired more than once, but i kill power to it each time so it dosnt burn up.

I tested the tip102 for continuity after install, leg 1 and 3 were good, and leg 2 was good on the solder side. I didnt notice a component side trace to check on leg 2, but i read about it since then.

"""""" if the new TIP102 transistor is not soldered in correctly, this can cause the
TIP102 to short again. This happens because the old TIP is hastly removed,
destroying the plated-through holes in the circuit board. After soldering the new
transistor, make sure all three transistor legs are connected to their traces. Use the
continuity feature of a DMM to test this. Particularly if the center leg does not
connect to the 1n4004 diode (trace on the component side of the board), the
TIP102 will work for one "fire" and then lock-on during game play and destroy itself.""""""

mine was locked on upon power up, before game play was started, if that makes a difference...

i will check this continuity tomorrow...

I will test tomorrow like this:

Coil disconnected
DMM on ohms
Red on tab
Black on braid

Thanks. Sparky

#13 1 year ago

Ok. I just did my tests.

First i checked for continuity from the tab to the diode, and it is good.

I then cheked the ohms of Q54.

Game in attract mode
Coil disconnected
Coin door closed
Dmm set to ohms
Black on braid
Red on tab
Reading was 4.20

I tested the transistors for the other 3 TED coils that are currently disconnected by the same plug.
Q52,56,58. They all show OL on my meter.

Does this confirm that the new transistor is bad?

Im honestly very confused by my readings since im getting OL on my good tips.
I should be getting the reading grumpy stated on my good tips.

I have to admit, that i dont use my ohm setting to often.

I have 2 meters. One is auto ranging, and the other isnt.

I keep retesting with both meters.
With coin door closed:
i am getting OL on the auto ranging meter, and
1 on the non auto ranging on every available selector switch setting.

With coin door open:
my auto range gets about
1.6 Mohms on Q52,54,56,58

MY manual select meter on 2000k setting shows:
Q52. 1111
Q54. 1045
Q56. 1041
Q58. 1151

Am i testing correctly?? Im confused.
Thanks. Sparky

#14 1 year ago
Quoted from SPARKY70:

I then cheked the ohms of Q54.

Game in attract mode
Coil disconnected
Coin door closed
Dmm set to ohms
Black on braid
Red on tab
Reading was 4.20

Sounds like a shorted TIP.

Quoted from SPARKY70:

With coin door open:
my auto range gets about
1.6 Mohms on Q52,54,56,58

See sometimes they test good when they are indeed bad.

I still refer to my earlier post.

Quoted from SPARKY70:

Any time you have a shorted driver, you always replace the shorted driver, predriver and diode

Quoted from SPARKY70:

Am i testing correctly?? Im confused.
Thanks. Sparky

Yes you are testing correctly but different DMMs will give different readings so pick your favorite meter and get familiar with what it reads for a new TIP and predriver out of circuit. Check a good diode and note the readings too.

#15 1 year ago

I just realized that you purchased this game with this problem. Please do me a favor and remove J127 and leave it disconnected for the remainder of your tests. Also verify there is no connector on J129, as it's unused in your game. I'm asking you to do this as I don't trust the playfield wiring since this problem existed at the time of purchase.

Re-check the same items Grumpy had you test, if you still have a bad reading on the TIP102 then replace it.

Quoted from SPARKY70:

Here is a tech tip I learned the hard way. Any time you have a shorted driver, you always replace the shorted driver, predriver and diode and also test the coil for the correct ohms. This only cost you an additional .60 cents in parts and will save you lots of time and frustration.

I personally never do this, but I understand the reasoning behind it, especially on an unknown machine as you have no idea what a previous tech did to this game, and the cost is definitely not prohibitive. If your confident in your soldering abilities then I say go for it.

#16 1 year ago

Other thoughts...

Your new transistor should not have blown this fast so what could have caused it to blow?

1)

Quoted from SPARKY70:i read something about the center leg needing to make contact on the component side, and if not, the coil will fire once, then blow the tip 102. Mine has fired more than once, but i kill power to it each time so it dosn't burn up.

This can happen if the thru hole or trace was damaged when removing the TIP102 as this would break the connection the flyback diode. Without the flyback diode an excessively high voltage will be applied to the drive transistor when it turns off; this will destroy the transistor, the number of hits it can survive depends on the transistor.

Testing procedure ... perform a resistance check between the metal tab on the transistor and the anode side of the flyback diode. Note, the anode is the side WITHOUT the stripe.

2) Installing a coil with a diode and hooking up the wires incorrectly, performing this action will usually blow your fuse, destroy both the coil diode and the drive transistor due to excessive current flow. Under these circumstances your coil should not fire unless the diode burns open removing it from the equation; however this is not the normal fail mode for rectifier diodes.

3) Your flyback diode (D22) was replaced backwards. This instance would result in the same conditions as listed in number 2.

#17 1 year ago

hi grumpy and pinguy.

I just checked J129, and it has nothing connected to it.

to be clear, the statement quoted in pinguys last post was actually quoted from grumpy, but i had pasted it into my first post so it may have looked like mine.

earlier today, before you made your last 2 posts, i decided to replace my tip102 again.
i decided to only replace that one transistor as to not introduce any new additional problems, by messing with more of the board.

i figured i can still replace the diode and pre driver after i see what happened.

so after replacing the Q54 transistor, i plugged ted back in,
turned the game on, and the eyelid up coil would lock on momentarily, then released.
but then the eyelids would close and work properly during gameplay, and test mode, but the occasionally lock on again.

i think the first transistor that i used may have actually still been good, and was just locking on intermittently, but i never gave it a chance to not lock on.

so something is obviously still wrong.

i disconnected ted again, as to not burn up the coil.

not that it means much, but the game did not seem to be abused before i got it.
i think it may have been only used in a home. it was dirty, but it cleaned up very nice.
still has all matching serial number boards, and they all looked untouched.

there are barely any marks on the game, in other words, it was not a basket case..

where do i go from here/ thanks//sparky

#18 1 year ago

ooopss

#19 1 year ago
Quoted from Pin_Guy:

Other thoughts...

Testing procedure ... perform a resistance check between the metal tab on the transistor and the anode side of the flyback diode. Note, the anode is the side WITHOUT the stripe.

i just did this test:
game off
meter on 2000K ohms
one lead on metal tab.
other lead on non striped side of D22 diode.
reading was 000

i did not replace the diode, but i see that the stripe is on the RIGHT side of the diode.
that is the same side as Q52,54,56 in the same column of transistors.

#20 1 year ago
Quoted from SPARKY70:

Testing procedure ... perform a resistance check between the metal tab on the transistor and the anode side of the flyback diode. Note, the anode is the side WITHOUT the stripe.

i just did this test:
game off
meter on 2000K ohms
one lead on metal tab.
other lead on non striped side of D22 diode.
reading was 000

That's exactly what you should have, so you know it its making good contact.

Quoted from SPARKY70:

not that it means much, but the game did not seem to be abused before i got it.
i think it may have been only used in a home. it was dirty, but it cleaned up very nice.
still has all matching serial number boards, and they all looked untouched.

there are barely any marks on the game, in other words, it was not a basket case..

That huge, and it does mean a lot, sounds like you found a gem with a relatively minor issue.

Usually intermittent problems are connection problems, possibly related to data lines. The thing I don't like is that you are only seeing an issue with one solenoid; while its unlikely, you can have an intermittent problem with the Sol3 clock signal from the MPU; a quick and easy way to rule this out would be to flip over your ribbon cable between the MPU and PDB, this would place the current Sol3 clock wire on an unused pin. If this or data line 4 had an issue, you really should see this across multiple coils though

#21 1 year ago

yes, the game is now beautiful otherwise.

Quoted from Pin_Guy:

Usually intermittent problems are connection problems, possibly related to data lines. The thing I don't like is that you are only seeing an issue with one solenoid; while its unlikely, you can have an intermittent problem with the Sol3 clock signal from the MPU; a quick and easy way to rule this out would be to flip over your ribbon cable between the MPU and PDB, this would place the current Sol3 clock wire on an unused pin.

i will give this a try tomorrow. im heading to bed now.. ill report back..thank you...sparky

#22 1 year ago

Ok, i just flipped the ribbon cable at J113 to the Cpu.
The problem is still intermittent.

Similar to the way a fuse can be substituted with a circuit breaker so you dont go through a handful of $1 fuses during diagnosis, Im curious if there is a way to substitute a coil with a buzzer or something so that you dont blow through $11 coils during tests. Mine is starting to overheat a bit.

Thanks for your help. Sparky.

#23 1 year ago
Quoted from SPARKY70:

Similar to the way a fuse can be substituted with a circuit breaker so you dont go through a handful of $1 fuses during diagnosis, Im curious if there is a way to substitute a coil with a buzzer or something so that you dont blow through $11 coils during tests.

There is a testing procedure where you can substitute a 12V Lamp for your coil and use the TIP102 to activate it, but it can be a little dangerous if not done properly.
I know how to do it, but I believe Zaza made a nice graphic of how to do it, if your interested I can see if I can find it.

#24 1 year ago

Since its a bit dangerous, Ill hold off on that for now.

Anything else i can check? Thanks

#25 1 year ago
Quoted from SPARKY70:

if there is a way to substitute a coil with a buzzer or something

Quoted from Pin_Guy:

but I believe Zaza made a nice graphic of how to do it

Can't find it right now but it must have been something like this.
When you do this, best pull connector from J102 and J122 to J132 to work safe.

test sol11 (resized).jpg

Quoted from SPARKY70:

i think the first transistor that i used may have actually still been good, and was just locking on intermittently,

Could be a problem with a resistor as well. Check all components in the circuit of solenoid#11, from R90 to D22 in the picture.

#26 1 year ago

Thanks again zaza.

Before i try your test light setup, i will test the resistors and diode and see what i get.

Thanks. Sparky

#27 1 year ago

ok, i just tested all the resistors and the diode for sol 11.

below are the values.
all tests are in circuit, but the coil is disconnected by its plug.
power off.

r90 .477 kohm
r91 4.80 kohm
r92 2.035 kohm
r93 68.1 ohm

d22 .344 tested in circuit

i did some comparisons, and i have an idea of what might be going on, but id like to hear from you guys first to confirm.

thanks///sparky

#28 1 year ago

The resistors are very much the same as here on the testboard.
The diode seems lower than normal. I've readings more like 480-500mV. I would replace D22.

#29 1 year ago

Yes zaza, thats exactly what i had thought.
The reading appears low, plus my other 3 Disconnected TED coils had diode readings of about .555, so this one stood out as likely bad.

Grumpy said that he always replaces the diode with the 2 transistors. Now i understand why.

I will swap it out, and report back.

Thanks, sparky

#30 1 year ago
Quoted from SPARKY70:

Grumpy said that he always replaces the diode with the 2 transistors. Now i understand why.

Quoted from SPARKY70:

I will swap it out, and report back.

Swap all 3 parts just to humor an old man.

#31 1 year ago

Lol, ive got to see if i have the pre driver on hand. I have a handful of 2n4401’s. I thought they would be the same as my high speed, but they are not. Sparky

#32 1 year ago

Sorry, ive been very bust the past few days.

I picked up the correct pre drivers.

I removed the driver board, and noticed that Q54 leg 3 (emitter) looked blackened.

I tested for continuity, and noticed that the tab/leg 2, and keg 3 had continuity.

So i replaced Q 54 again, along with Q53, and diode 22.

Afterwards, i noticed that the Q54 still had continuity between leg 2 and 3.

I removed Q54, and i still have continuity on the board from hole 2 to hole 3, with the board out of game.

I am no expert, but i have a good feeling that this should not be.

I dont see any solder connecting these two holes on either side of the board.

Can you guys please confirm whether or not these two should have continuity or not?

Also if they should not, what else could i check to see why these two holes have continuity.. thank you all. Sparky

#33 1 year ago

Hole 2 (collector) and 3 (emittor) should not have continuity.

Follow trace from hole2 to J127-4 / J129-4 and check for metal/solder that doesn't belong on this path.
The only component on this trace is the anode-side of D22. (Cathode goes to +50V)

#34 1 year ago
Quoted from zaza:

Follow trace from hole2 to J127-4 / J129-4 and check for metal/solder that doesn't belong on this path.

I just rechecked this over and over, and i dont see anything.

#35 1 year ago

How about a pic of both sides.

#36 1 year ago
Quoted from zaza:

The only component on this trace is the anode-side of D22. (Cathode goes to +50V)

This side also seems to be free of any unwanted solder.

I am getting contact all the way from the right side of R92, all the way down to J129-4.

I dont visually see anything causing unwanted contact.

I have to also note, tgat my meter has an audible tone for continuity.

I have noticed that it seems to tone for a moment, then pause for a moment, then tone.

Tone-pause-tooooooooooooooone.

This happens about 9 out of 10 times, which is not the norm for my meter.

Could there be something else causing this continuity?? Thanks. Sparky

#37 1 year ago

Hi grumpy, here are pics of both sides.

The component side got a little charred looking between hole 2 and 3.

Solder pads 1 and 3 on the back separated after the 4th removal of Q54. Thanks. Sparky

99E3AB72-823D-4155-81EF-2A9A409EED96 (resized).jpegFA5F8F22-7118-4305-9E1E-845EC4A37C51 (resized).jpeg

#38 1 year ago
Quoted from SPARKY70:

a little charred looking between hole 2 and 3

It is possibe conductive. Try to remove the blackened area and measure again for continuity.
This is also one of the few places where output and ground are close together.

sol11 short (resized).jpg

#39 1 year ago

Sorry to keep everybody in suspense, ive been very busy.

I scraped away some of the black with a toothpick, and the continuity stopped, so that was the issue.

Thanks for the suggestion, I never knew that could be a cause.

What is the best way to make sure i remove enough or nuetralize to make sure it does not re-occur? Thank you.

#40 1 year ago
Quoted from SPARKY70:

What is the best way to make sure i remove enough or nuetralize to make sure it does not re-occur?

I normally use a Xacto knife to remove the carbon deposits. If you need to build up the board use some super glue.

pasted_image (resized).png
#41 1 year ago

Thanks grumpy, ill give that a shot.
What is a good way to handle the solder pads on the rear since they do not have any traces?

The trough hole on the center hole has continuity as it should.

Also, the mask is partially missing on one of the traces (see pic). Is this a concern, or should i cover with something?
Thanks again. Sparky.

#42 1 year ago
Quoted from SPARKY70:

What is a good way to handle the solder pads on the rear since they do not have any traces?

You can buy circuit board trace repair kits that contain different size eyelets to make this repair.

Quoted from SPARKY70:

Also, the mask is partially missing on one of the traces (see pic). Is this a concern, or should i cover with something?

You need to decide whether this is a concern depending on each situation. If it does need to be repaired then you can use a green colored nail polish for small repairs, you will need to mask off the solder eyelets first.

pasted_image (resized).png
#43 1 year ago
Quoted from GRUMPY:

I normally use a Xacto knife to remove the carbon deposits. If you need to build up the board use some super glue.

This will work fine.

The following information is provided for information only and not recommended for a single board repair.

Pro tip:
My main goal on every repair is for the board to look like it was never repaired.

For this type work I use a high speed drill with a ball mill to grind out the damaged area. I will typically fill the ground area with epoxy http://www.circuitrework.com/features/627.html there are dyes available to add to the epoxy in order to match it with the PCB color http://www.circuitmedic.com/products/115-1322.shtml. When grinding out an area next to a pad/trace like yours, I will usually pre-drill the pad for a replacement eyelet, then heat and lift the pad out of the way before grinding in order to avoid damaging this connection point...the broken thru-hole will be fixed in the next step.

Quoted from SPARKY70:

What is a good way to handle the solder pads on the rear since they do not have any traces?

The best fix (permanent) is to install circuit board eyelets of the appropriate size, this involves drilling a slightly larger hole through the board in order to accommodate the eyelet. If a run is involved with an intact pad, you install the eyelet thru this connection point and pre-solder these points to ensure a solid connection before installing your component; this involves filling the hole AND flowing the connection between the pad and trace.

NOTE: most people will not have any of the materials mentioned here to do this type of work; the cost of obtaining these items is very high and not cost effective for repairing a single board.

#44 1 year ago

Hi pin guy, thank you for the additional info. I will check out those links.

Im not sure if i explained correctly, but i believe my center hole is fine because it is making contact through the board as it should.

The left and right hole are just missing the pads on the solder side, so i think the eyelet isnt needed in my case??

Is this correct? Thanks. Sparky

#45 1 year ago

What Pin_Guy is saying is, the best way to hold the solder pad in place would be to install a eyelet. He knows that the original didn't have one. Now this may not be very cost effective for you to do this for just 2 pads, that is why I suggested that you can just install a pad and solder both sides of the board as this will give the component far more holding strength then just soldering the top side of the board.

#46 1 year ago
Quoted from SPARKY70:

Hi pin guy, thank you for the additional info. I will check out those links.

Im not sure if i explained correctly, but i believe my center hole is fine because it is making contact through the board as it should.

The left and right hole are just missing the pads on the solder side, so i think the eyelet isnt needed in my case??

it's not, I like to provide additional information as you never know who all will come across this thread. The links are additional information on how to repair scorched boards and the products available to perform the repair. But again, none of this is directed at repairing a single board.

#47 1 year ago

Ok, i understand. Thank you grumpy and pin guy for clarifying.

I will look for the replaacemant pads, and hopefully that will be the end of this issue.

During this whole process, the mini coil in Teds head got a bit overheated.

The wrapper got a little funny, but the plunger still slides through.

Out of curiosity, can this coil condition cause any further issues?

If so, i dont waant to put the board back in to test before i change the coil.

Thanks. Sparky

#49 1 year ago

Hi grumpy, thanks for the link.sorry i couldnt get back here sooner. Very busy with alot of things plus a lot end of year school stuff with my kids.

I took a look, and my coil in question is not listed.

I looked for similar numbered coils, and found 2, but neither have a resistance listed.

SM-31-900-DC

I stopped into my local electronics shop, but he does not have the solder pad set like you pictured.

I will keep looking. Thanks. Sparky

#50 1 year ago
Quoted from SPARKY70:

I stopped into my local electronics shop, but he does not have the solder pad set like you pictured.

I'm not surprised as unfortunately this type of work is no longer mainstream

Here is a link to the board repair kits, you will need to pick out the one(s) that best fit the type of repair you are performing.
https://www.all-spec.com/Catalog/Soldering-Rework/PCB-Board-Assembly-and-Repair/Circuit-Board-Assembly-Repair-Kits

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