(Topic ID: 122913)

Stern Ta100 Rebuild

By RobW

9 years ago


Topic Heartbeat

Topic Stats

  • 16 posts
  • 7 Pinsiders participating
  • Latest reply 8 years ago by underlord
  • Topic is favorited by 2 Pinsiders

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Linked Games

  • Stars Stern Electronics, 1978

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#1 9 years ago

Just picked up a Stern Stars and in the process of rebuilding a bad power supply. I tested it when I got it and had low dcv at test point 2. It should be 230 vdc. Got a kit from Big daddy, soldered it in and waalaa. Nope same low volts about 7.5.

What did I do wrong? should I just get a brand spanking new one and let this board go?

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#2 9 years ago

There's a lot of solder bridges.

The board looks like it's in good condition (pads etc).

Try cleaning it up. Look for shorts; follow the traces. It's a very simple board (so easy, I was able to fix mine )

Test the BR.

faz

#3 9 years ago

Tried all that. Also forgot to mention, all xformer voltages are good

#4 8 years ago

This is killing me, Please ask questions!

#5 8 years ago

The solder joints at R3 and CR2 look questionable. Also clean up the solder at CR3. Those items are related to TP2.

Check voltage between E5 - E6. Check voltage at both ends of F2.

Take a photo of the back side of the board.

Like FAZ said it's an easy board to fix, especially the high voltage.

Let us know what you get.

Bob

#6 8 years ago

If you did some work to the board, please add some good quality photos of both sides of the board.
faz

#7 8 years ago

You've got destroyed pads and through-holes, lifted traces, globs of solder and cold solder joints.

You really need to take a step back and invest some time in learning how to solder (I'm presuming that's your work since you said you installed the Big Daddy kit). At this point the board is pretty much trash.

There are at least 5 destroyed pads/through-holes around the resistor and the four diodes.

Am I the only one who looked at the enlarged image?

#8 8 years ago

I still think you can fix it. Keep in mind... I put my board skills somewhere above novice, but this is about the simplest power board you will ever see.

Look at this repair that Steve did to the same board.

http://stevekulpa.net/pinrepair/stern_psta100.htm

Add some stitches to complete the circuit where the pads are gone.

Find a schematic, look at pictures, plan your work. Discuss your plan with the group.

Again, get some high res photos of both sides of the board. (I'd like a better angle or more angles of the top... it's hard to see with all those components).

I hate to ask what it looks like under the bridges.
faz

#9 8 years ago

It could be fixed by someone with more than novice soldering ability. Based on the current solder work I dont see that happening in this case. Just being realistic.

#10 8 years ago

I'll say that the damage on the board is now way beyond the "average joe with a soldering iron" repair skill set.

The rectifier board needs to be 100% reliable or the game will constantly be flaky.

I say get a new board, but let someone more experienced solder the transformer wires onto it.

Save this board so in the future, once you know how to solder, you can look back at it.

#11 8 years ago

As mentioned above -- lifted and missing traces for HV circuit.
Cathode (banded end) of CR3 to anode (non-banded end) of CR2. Should be trace between the two. Possibly bad connection back to E6 but hard to tell.

Missing trace to R3 as well. Hard to see other HV connections that are blocked from view as well as back side.

I believe Steve Kulpa (mentioned above) can get you going again.

#12 8 years ago
Quoted from G-P-E:

I believe Steve Kulpa (mentioned above) can get you going again.

Almost the same price as buying a brand new (better) board.

Add on a few bucks for the repair and round trip shipping and I'd say a brand new board makes more sense.

Don't forget that any further service on that old board, even if Kulpa fixes it, will probably be much more difficult.

https://greatplainselectronics.com/proddetail.asp?prod=135-105

#13 8 years ago

Thanks guys,

Like I said this was in really bad shape when I got it. Ive taken it apart cleaned and re-soldered a couple of times. Probably not the best idea when frustrated. That is what brought me here to this site. I thought I had pretty good soldering skills.

I have the Schematic and all points test continuity.

Back of cr4 and cr3, E6 to to the back of cr2 and the front of cr3.
E5 to the back of cr1 and the front of cr4
189 vdc at the front of cr1 cr2 and r3
Bridges test fine

Still bewildered,
Rob

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#14 8 years ago

Sorry Bob , I didn't answer your question

Voltage at e5 e6 is 185vac
Both ends of f2 133vac

#16 8 years ago
Quoted from RobW:

Thanks guys,
Like I said this was in really bad shape when I got it. Ive taken it apart cleaned and re-soldered a couple of times. Probably not the best idea when frustrated. That is what brought me here to this site. I thought I had pretty good soldering skills.
I have the Schematic and all points test continuity.
Back of cr4 and cr3, E6 to to the back of cr2 and the front of cr3.
E5 to the back of cr1 and the front of cr4
189 vdc at the front of cr1 cr2 and r3
Bridges test fine
Still bewildered,
Rob

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