Intermittent sound issues with my Firepower... I guess time has come to re-cap the sound board (see hole in cap on picture below!)... But... Won't be easy to desolder caps from this huge ground plane!

IMG-7879 (resized).jpg

Check the DIP sockets on the sound card. I was having intermittent issues with my Blackout and replacing the original sockets with quality machine pin sockets fixed it.

You are correct. The huge ground plane makes it a little rough. I got everything out okay, but getting the holes cleared was a little frustrating. I used a solder sucker (the clicky tube type). I found that adding some new solder helped.

I agree with Robotworkshop about the sockets. I have a similar issue I am working on with my Black Knight and I have recapped the board. Oddly, my issue has now reversed. It used to take 20 - 40 minutes for the sound to finally kick in. Now I get sound immediately, but if I turn off the machine for any reason, I then have no sound. That's just weird. I was hot on the trail of fixing it, but my mom passed away last week and I have been sort of reeling from that. But I will get back at it at some point soon.

Hey, something else to add. Make sure you reflow all the connectors. I took like an hour and reflowed every solder point on the board (just to make sure). You have to make sure you are very careful not to over heat anything though. I like to use a really hot iron. Get in, flow it, and get off as fast as possible.

That's a vent hole, so if the capacitor pops it does so from a controlled point rather than exploding all over the place.

Huh! Sorry the sound is flaky. It did go out on me a couple times over the years while tinkering with it but I thought I had it fixed. As I'm sure you know it can be tricky chasing down intermittents.

All of the header pins on each board have been re-flowed already; as someone else mentioned the sockets can be problematic and the ribbon cable between the sound board and speech board can, too. I'm not certain if it can be a source of the sound going out but since the speech board has the "mixer" knob on it that lets you balance sound effect:speech volume level, I'd think it's at least a suspect (the ribbon cable between the boards, that is.)

Richard

No problem at all! I signed up for this type of thing, that's what happens with electronics from the 80s I'm going to troubleshoot a bit more. I was hoping the hole in the cap could be a root cause, but if such vent hole is expected, maybe not. Won't hurt to replace it anyway.

Those largebground planes can make removing parts a pain. I've had my son help with a second iron on the other side of the PCB for difficult ones.

I'm having trouble with occasional resets on Gorgar. Pinwiki led me to check the unregulated 12V, and while I understand it can vary, I'm only getting 10V. I traced the 10V all the way back to the diodes on the power board, which are new 6A4 diodes that I installed per this guide. I'm getting 9.5 VAC on the other side of the diodes, which looks correct per the schematic.

Granted this was tested when it booted up fine. My guess is 10V is borderline ok, but it's occasionally dropping below that and causing the reset. What should I be changing or checking here if that's the case? New diodes again? Or does it sound more like I'm going down the wrong path with the reset issue?

So on one side of each diode, you are getting 9.5V AC and on the other side of the diodes, you are getting 10V DC? You should be seeing much more than 10V if both diodes are good with a 9.5AC input.

Measure DC volts between ground and each clip of F5 and tell us what you are seeing.

Remove F5 and tell us what DC voltage you see at the F5 clip (this will be the unloaded voltage).

I would look closely at the pins in J1 for loose, tarnished, worn out connections. Does J1 show any signs of getting warm (yellowed or burned housing)?

I first checked at the MPU and that's where I saw 10V, at TP1. Then checked at the MPU connector, then power supply connector, fuse, capacitor, and diodes. Same everywhere.

I'm getting 10.0 VDC at each clip with F5 in, and 13.1 VDC with F5 removed.

6 Being toasty might have been caused by the board being from another game that uses pin 6. Pin 3 is for flipper power so I can't see that as the cause of your issue. I would order a replacement wafer connector and pins from GPE and replace them when you get a chance.

Look below the power board, there are several fuses mounted on the backbox. There is a pair of 4A SB fuses there labeled F2 and F3. These fuse the power supply as it enters the power supply board. Using your meter on AC, measure from ground to each side of these fuses in these fuse holder as well as the inputs to the diodes on the power supply board. You are looking for a voltage drop caused by a dirty connection somewhere. After you measure, remove these fuses, clean with a green scrubby or something, reinstall and remeasure to see if things improved.

I had one explode on me, in a monitor, after I'd installed it backward. Looked like confetti in my hair.

I installed one with too low voltage on my PSU a while ago. One of the loudest noises I've ever heard. Was fun cleaning all the confetti feather crap out of the game..

Before:
10.0 to 9.5 VAC, and 9.7 to 9.6 VAC

Didn't do a great job of cleaning those fuse clips with the big cap in the way, but I looked at the fuse for the one with the 0.5V drop, and it was measuring about 5 Ohms resistance. It was also a 1/4A fuse! I replaced that with a 2.5A SB fuse (don't have any 4A on hand).

After:
9.9 to 9.8 VAC, and 9.8 to 9.8 VAC
Diodes both measured 9.8 VAC going in and 11.1 VDC coming out.

MPU TP1 is now getting 11.0 VDC, so definitely an improvement over where I started. Anything else I should be looking at? If not I'll just keep an eye on it and see if I get any more resets.

Nice find!

Looking at the reset circuit, I can't see how a voltage over 7ish volts on the 12v circuit would cause resets. Since 5v is derived from the same source as the unregulated 12v, I would play it for a while and see how things go.

Performed the fire proofing on my project Laser Ball, "fired up" the game last nite and voila, all is well!
Thanks Vid.

Thanks to Peter ( Inkochnito ) , I modified his fuse chart to take into account the additional fuses.

fuse chart (resized).jpg

fuses (resized).jpg

I am working through this post on a High Speed that has sat for quite some time. Before and after replacing caps, I am getting 12v on the 5v test point. I think the transistor is bad. Have a new one on the way.

I assume the high voltage changes apply to system 11, as well. My problem is the component layout is slightly different from the image on page 2 of this post. I am not able to find a component layout for the System 11 power board. Can someone point out the resistor and diode numbers or point me to an image with the components labeled?

C5151D0F-4274-46A3-943C-745B16C7FEC7 (resized).jpeg

page 49 of 63 from this file?

https://www.ipdb.org/files/1176/Williams_1986_High_Speed_Instruction_Manual.pdf

Atari_Daze
Thanks! I had seen a page like that before, but it didn’t have the labels. That is very helpful.

NP, bookmark that site, it's invaluable!

Even after cleaning original GI fuse holder it would fail under load(buzz and spark). I could see how someone could test fuse and move on to further problem solving not knowing the fuse holder is failing. There have been a few approaches on replacing old fuse holders. Here is a picture of my solution and another pinsiders solution. Bottom photo he divided 4 GI(20amp fuse) into 4 separate 5amp fuses. Top pic, I divides into two 10 amp fuses. The biggest problem with putting all 4 together as seen in original is soldering a 4 wires on one little fuse tab as seen in second picture. Do not like this mounted in the front(game had this hack). Hope this helps. Simple easy clean look now.

IMG_0315 (resized).jpgafpbk (resized).jpg

What works for tip41c in sys6? Can you use IRF9Z34N or IRFZ34NPBF? Are these different or the same thing. I'm assuming whatever you use it's recommended to keep resistors in?
Thanks

This is what I installed in my Black Knight. it is soooo much better than the nest of parts and wires. Marco and BDE sell this. I also installed this in my Sega BW.

download (resized).jpeg

I made a schematic of the PFET replacement for the TIP42 lamp strobes on system 6/7 driver board.

Before and after.

Lamp Strobe TIP42 (resized).JPG

PFETpic (resized).jpg

Lamp Strobe PFET (resized).jpg

The PCHAN MOSFET operation is not intuitive for people like me used to using NPN transistors as switches.
I found a short tutorial online about PCHAN used as a high side switch that helped me understand why it works so well.
The tutorial circuit was modified to match the System 6/7 lamp strobe circuit.
This helped me understand it.

HighSide-PCHAN (resized).jpg

Got a new Alien Poker with a host of problems. One of the bridges was shorted and a few of the power resistors got so hot they desoldered themselves from the board! No fuses ever blew. I've got a new bridge and power resistor kit on the way, is it likely the PIA or any other parts were damaged?

I had the playfield up and heard something fall to the bottom of the cab. I saw the power resistor, not putting 2 and 2 together I picked it up and burned my fingerprints off.

Wow, sorry you got burned....
My first job on these old machines is to reduce heat inside mostly by LEDs and Switching power regulators instead of linear regulators.
But, on my first System 3-7 machine I saw the heat marks from those resistors on the driver board and I knew they had to go!
That is why the PFET change over was so appealing to me.
Of course I recommend getting rid of those power resistors and TIP42s on the lamp circuit like shown previously.
There is ZERO heat coming from that circuit on my machine now.
Also put the in-line 8A slo-blow fuse on each bridge rectifier like VID1900 recommends.
Also all the 9 pin Molex headers on the CPU and Driver board are now suspect, try re flowing the solder on all those like Todd Tuckey recommends. (I like to put in a dummy connector while I'm re-heating to keep those headers from distorting)
Of coarse, the 40 pin interconnection between CPU and Driver board needs replaced, ALWAYS!

I reflowed everything before I turned it on. Luckily somebody had already done sockets and the 40 pin (which looked good) at some point in its life. Planning on doing the fuses and all that just wondering what the chances were that the 7408s or any other parts were also trashed.

Does anybody have a source for the (.22mfd) caps shown in post #92? I can't seem to be able to find them.

wrong cap

Axial caps would fit better there than radial, since the originals are axial:

https://www.mouser.com/ProductDetail/Illinois-Capacitor-CDE/224MWR250K?qs=sGAEpiMZZMv1cc3ydrPrF6UOBDifjZuP02XcubzMPzvc7pAAKUZQtw%3D%3D

Thank You @sndchaser, also Kawydud for your reply. Now I can finish bulletproofing my power board with your help.

I am working on a Laser Ball and have replaced the sockets. I added a watch battery to the area where the battery holder was removed.

When I power it up and it displays what the picture is showing. “1493 2” up top, with maybe a digit out. The bottom display is “04 00”.

I read that this is because of batteries being dead, and was happening before I put the new holder in. So now no difference because of the battery.

I also read that if you have the game on, then flip the switch real quick that it will boot. Well, it does do that. The battery is supposed to fix that. So, I’m back to stuck, but a little further along. Any tips?

5DC67DC9-A295-42EE-BF7D-9C097C937B18 (resized).jpeg

I got it to boot. Next step is to figure out why the coil fuse is blowing.

Disconnect all the coil connectors (2J9, 2J11, 2J12).
Power-up the game and see if the fuse still blows.
If no, the problem is in one of the coils or it's drivers.
With the power still on, carefully connect one connector at a time.
At the moment of connecting the bad coil you will see a spark, which can lead to the bad coil.
Check the manual for the connection and the coil to check.

Peter

I ohm'd out all of the coils and they checked out as being ok. Should I also do diode testing on the drivers? Or am I likely looking at a different short? Prior to this, I don't remember a coil locking on ever, so might be a hidden short. I will see what I can find and report back.

Potentially dumb question, but that's never stopped me from asking things.

I'm working on a System 3 and just got back from the store buying a few things. Didn't really feel like buying a 50' spool of wire when I need less than 2'. One of the things I picked up was a 15' extension cord that I'm going to use to replace the power cord. Any issue with cutting off an extra foot when I chop off the female end of the extension cord and using the wire from within it for this rectifier fix? Packaging for the cord says it's 16 gauge. I assume there's no issue other than whatever colors the wires inside are, but any concerns beyond the purely cosmetic?

I can't possibly imagine any issues doing that.
-Mike

Thanks for the vote of confidence. Seemed so simple and obvious a solution, but just wanted to make sure.

When changing out the old tip42 to the irf9z34npbf units is there issues with running leds? I made the switch yesterday and now some groups of playfield lights stay on flickering.

I’ve never noticed a change in ghosting after the mosfet upgrade.

see video. These are the only light on the table doing it.

Likely the lamps PIA on the driver board. You can try these test ROMS: http://pincoder.ca (specifically the lamps test). If the lamps work using that ROM but not the Williams ROM you should try swapping PIA out.. The difference in the ROMs is in the refresh rate, and weaker PIAs cannot keep up to the williams refresh rate..

In the very least if they do run fine under the pincoder ROM you know the playfield wiring is good.

Can you use the same zero ohm resisters that is linked in post#132? Those are 1/4 watt but the originals are 2 watt. I already have the 1/4 watt, just trying to use what I have.

Absolutely. Wattage on a zero ohm resistor is meaningless anyway, it's just the cosmetics of the package size.

Thank you sndchaser

Should I even persist? ....

IMG_20190818_102021 (resized).jpg

IMG_20190818_102042 (resized).jpg

There are certainly better ones out there. Personally, I would fix it but put in the MOSfets to stop the damage.