(Topic ID: 248196)

1979 Bally Star Trek F4/J2 causing F6 fuse to blow


By Kahafer812

8 months ago



Topic Stats

  • 13 posts
  • 8 Pinsiders participating
  • Latest reply 8 months ago by wdennie
  • No one calls this topic a favorite

You

Linked Games

Topic Gallery

There have been 9 images uploaded to this topic. (View topic image gallery).

9 (resized).jpg
8 (resized).jpg
7 (resized).jpg
6 (resized).jpg
5 (resized).jpg
4 (resized).jpg
3 (resized).jpg
2 (resized).jpg
1 (resized).jpg

#1 8 months ago

I recently received a 1979 Bally Star Trek pinball machine from my father. Most everything was working well when I received it. I did need to replace the sound board and I threw some led lights in the back glass and replaced all fuses (with proper ones). Probably ran about 100 games or so through it over the course of 2 weeks. Mid-game one day she died on me.

I checked and the F6 fuse was blown, I narrowed it down to it only blowing when the F4 fuse is in place, and it also blows when only the J2 connector is plugged in. I checked all coils and am getting 10+ Ohms on all. I’ve gone up and down the play field 4-5 times and see no signs of anything fishy. F4 is the solenoid power supply and could fail as a result of bad BR3 rectifier or shorted R3 varistor (looks fine). But F4 isnt failing, F6 is only blowing when F4 fuse is in place. The R3 Varistor looks perfect, there is a place on the wood behind it that suggest one has most definitely blown before but the current one looks good. So I’m curious if the only real possibility is a bad bridge rectifier.

Also noticed I’m only getting about 1 volt (5.4 to 7 needed) on TP1 for switched lights on play field and backbox but can’t really see if they are working correctly as game won’t full boot with f4 not working.

Could a stuck on solenoid be causing this? I’m kind of hoping it is just a bridge rectifier to be honest because I wouldn’t mind just purchasing a brand new rectifier board all together since this one is original and 40 years old.
1 (resized).jpg5 (resized).jpg2 (resized).jpg4 (resized).jpg9 (resized).jpg8 (resized).jpg6 (resized).jpg7 (resized).jpg3 (resized).jpg

#2 8 months ago

Welcome to Pinside! I've suggested to the moderators they move your post to the tech area (early ss) where it's most likely to be seen by people willing and able to help you.

Other resources: Pinwiki- http://www.pinwiki.com/wiki/index.php?title=Bally/Stern#Bally_-54_Rectifier_board
Pinrepair- http://www.pinrepair.com/

#3 8 months ago

Did you replace F6 with a 3 amp slow blow? That's the spec.

If you turn the machine on with only j2 on the rectifier board connected and all the other connectors off the boards in the backbox, does it still blow?

The couple of things I'd suspect is the MOV on the silver RF filter box in the cabinet, you took a pic of it and there seems to have been some magic smoke deposited on the cabinet. That would cause the main line fuse to blow, as would a bad RF filter. You can temporarily take this box out of the circuit to test this theory and just buy a new one if it seems to work (make sure you unplug the machine from the wall before fooling with this, there's AC voltage right there). You'd take the filter out of circuit by removing the wires and splicing them together with wire nuts (for testing only.... that's not a long term solution).

You can test the bridge rectifier for the solenoids with a multimeter, pinwiki link yopp posted can help with that. It wouldn't hurt to get a new rectifier board as you said it is 41 years old. You'd probably need to repin the connectors as well but if the machine was in a nice climate controlled environment for a long time they might be ok.

You can take the under playfield fuse out to isolate a stuck on solenoid on the playfield. It's not the coil that goes bad (usually) but one of the driver transistors.
Stuck on coil regardless of reason should blow the playfield fuse or the F4 fuse.

#4 8 months ago

Yes, I've blown 3 3A 250v slow burns, that's a fast acting in there now just for testing it's all I had. Getting more SBs tomorrow.

Yes, F6 Blows with only J2 plugged into the rectifier board.

I didn't suspect the MOV as it was in perfect condition (bad pic wiring in way) RF filter remains possible but could that still be it even when everything runs fine without the F4 fuse in place?

I ruled out anything on the Solenoid board by unplugging all connectors from it and still blowing F6 (wasn't sure if J2 only being plugged into the rectifier board achieved this).

Seems a stuck on solenoid is ruled out as I've never blown the playfield or F4 fuse. (?)

So I'm thinking get some bridge rectifier numbers first (still hoping this is it as its something I wanted to replace regardless)

If that's not it, focus on the RF filter???

Would the only third possibility at this point be a short in the playfield somewhere?

Sorry if my line of thinking is off

#5 8 months ago

What are all your test point voltages on the rectifier board (TP1-TP5)?
That's a good place to start.

#6 8 months ago
Quoted from Enaud:

What are all your test point voltages on the rectifier board (TP1-TP5)?
That's a good place to start.

TP1 - 2.3 (Low)
TP2 - 232
TP3 - 13.77
TP4 - 6.2
TP5 - Not sure how to get reading without F4 fuse

#7 8 months ago

Might sound kind of stupid but it's worth a try pull all the LEDs out that you put in there and put the old bulbs back in and see if it keeps blowing fuses.

If it was working before and then started doing this after you changed all the bulbs, I put the game right back the way it was when you got it.

#8 8 months ago
Quoted from timab2000:

Might sound kind of stupid but it's worth a try pull all the LEDs out that you put in there and put the old bulbs back in and see if it keeps blowing fuses.
If it was working before and then started doing this after you changed all the bulbs, I put the game right back the way it was when you got it.

Pulled all LEDs and all bulbs I've changed out on playfield, still no luck.

Hearing a low brrrr tone coming from around the line filter when it blows. Thinking about bypassing that next to see if that's it before I go about switching out the rectifier board.

#9 8 months ago
Quoted from Kahafer812:

I’m kind of hoping it is just a bridge rectifier to be honest because I wouldn’t mind just purchasing a brand new rectifier board all together since this one is original and 40 years old.

Thats what I did- Once you factor 3 bridges, diodes for the high voltage displays, connector pins and fuse holders and shipping, $58 bucks for a new board with more robust bridges is a no brainer.

1 week later
#10 8 months ago

Here are my notes:
J2 is the cabinet connector. It brings the ac line into the transformer so, nothing will blow or turn on unless J2 is attached. Does anything blow if only J2 is plugged in?
If the fuse is not blowing with J2 unplugged the line filter and cabinet wiring is fine.
With J1 and J3 removed that eliminates the playfield and the backbox from the equation. The cabinet is still connected. Check the Coin door lockout and the knocker and make sure they are not shorting. remove J2-7 from J2 to be sure there isn't a cabinet 43v short.
If the above checks out you are probably due for a new rectifier board.
Finally, you need to remove the original NiCad battery from the MPU and replace it with an NV RAM. You also appear to have the original filter caps on the power supply board. You should order a capkit and replace those. Reflow all the pins on the boards when you remove them.

#11 8 months ago
Quoted from BigAl56:

Finally, you need to remove the original NiCad battery from the MPU and replace it with an NV RAM.

Or just leave it off all together and do nothing further, you lose high score and credits when the machine is turned off but no big deal there.

It is what I did with mine.

#12 8 months ago
Quoted from BigAl56:

Here are my notes:
J2 is the cabinet connector. It brings the ac line into the transformer so, nothing will blow or turn on unless J2 is attached. Does anything blow if only J2 is plugged in?
If the fuse is not blowing with J2 unplugged the line filter and cabinet wiring is fine.
With J1 and J3 removed that eliminates the playfield and the backbox from the equation. The cabinet is still connected. Check the Coin door lockout and the knocker and make sure they are not shorting. remove J2-7 from J2 to be sure there isn't a cabinet 43v short.
If the above checks out you are probably due for a new rectifier board.
Finally, you need to remove the original NiCad battery from the MPU and replace it with an NV RAM. You also appear to have the original filter caps on the power supply board. You should order a capkit and replace those. Reflow all the pins on the boards when you remove them.

Thanks for the post!

Yes, F6 blows when only J2 is plugged in along with F4 fuse, with F4 fuse removed nothing blows.

"If the fuse is not blowing with J2 unplugged the line filter and cabinet wiring is fine." How would I test this as I can't turn on the machine without J2 plugged in?

The coin door lockout is disconnected and the knocker is good.

I removed J2-7 and the machine wouldn't turn on at all. I'm showing J2-7 as "AC Line, low" is this correct? I noticed J2-2 is +43 vdc Solenoid Buss was wondering if you meant that one?

#13 8 months ago

I'd just replace that board, 40 years old, you'll fix one problem and a week later have a new problem, or bad cap or another bridge go etc.
Nice new clean power.

Promoted items from the Pinside Marketplace
From: $ 40.00
Cabinet - Other
Rock Custom Pinball
From: $ 155.00
Trade
Machine - For Trade
Bethlehem, PA

Hey there! Got a moment?

Great to see you're enjoying Pinside! Did you know Pinside is able to run thanks to donations from our visitors? Please donate to Pinside, support the site and get anext to your username to show for it! Donate to Pinside