I have a great deal of respect for your knowledge and I look forward to lending a hand to others when I'm ready.

I am working on a #Black Hole that has a solid 8V (8.17) and 5V (4.99) output (with just J1 plugged in). The 42V (47.3) and 60V (65) outs are solid. Powering down and connecting J2 voltages remain the same. Powering down and then connecting J3 (A2J3) the low voltage is unaffected but the 60V drops to 47.3 and the 42V drops to 22.49.

My questions are:
1) The 47.3V and 65V are within range or do I have a weak Zener?
2) With the 47.3V and 65V falling to 22.49 and 47.3 respectively is this a normal voltage drop from the load or a problem in the power board or excessive load from a problem board down stream.

Thanks, Tom
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Any words on this would be greatly appreciated. @Black Hole

Tom

Correct no displays. By the way this is a first time powering this game up.

With just the Status Display (A5) connected I have the following readings on the power supply:
TP4) 4.99v
TP5) 8.10
TP1) 63.6
TP2) 45.6

The Status Display has a zero diplayed.
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If I add any one of the 4 player displayes or the lower playfield display I get the following readings at the power supply:

TP4) 4.99v
TP5) 8.19
TP1) 44.1 - 52.9
TP2) 26.53 - 35.38

Non of the singly connected displays show any digets. If I plug them all in non of the displays function including the Status display. It drages the voltages way down.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

I could guess that all five displays are bad (but all 5 doesn't seem so likley). Can I test these or is it a CPU Boot issue or what? New to system 80. - Tom

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Well what I did find was with the player one display plugged in I get 59.9 vdc between pins 17-19 & 5.54 vac between pins 15 & 16. I did notice that when I power off the machine player 1 display flashed for a millisecond.

With acceptable voltages present it would seem ALL the segment drivers are not getting the proper signal to fire. This would lead me to believe there is a problem in the Control Board. Any thoughts?

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No, I did a continuity test out to the displays. All is good there. I did just pull the board and found a modification that has been done and one of the wires has come off. I have no way of telling where it went with any certainty. Anybody have any ideas as to what repair was being done? I'm assuming it has somthing to do with the segment driver signals out to the displays. - Tom

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Look what I found under magnification on the flip side of the chip that has just the one wire connected to it. I think I know where the loose wire goes. They cliped off both the legs where the wires were jumped to/from.
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It looks close from this angle but theres about 3/64th gap. I'll be powering this up in just a few minutes. Hope it will work.

Nothing...

Well I had an old control board and plugged it in and it booted.

Attract Mode:
All voices seem to be working when in attract mode but none in game mode.
All standard and controlled lighting seems to work on both fields. Back glass also but chaser lights are dim and very fast.
Displays. 1st and 2nd player only show one’s (111,111 & cycle to 1,111). 3 and 4 player display show what is pictured so again segments are missing (Control Board malfunction?). Lower Playfield display and Credit/Ball in Play displays are not lit during Attract Mode.

Game Play:
1st Player Display only shows partial segments when scoring. Credit shows only a 1 as does Ball. Its blank when advanced past the number 1.
No voice in game mode.
No Pop Bumpers, lamps are lit and solenoid voltage is available.
Yellow Targets, lit but no points or sounds
Drop Targets, only C&K make sound and score in BLACK and none of HOLE. They only reset on next balls start.
Front Left Bumper makes no sound and no points if it gives any.
Spinner makes no sound and no points if it gives any.
Gravity Tunnel Roll Over (to power up lower player field) does not function (leaf switch is ok).
Last picture is of it trying to show a score while playing.

Questions
Are the display issues all from the Control Board? I suppose these are chip &/or transistor issues. Any idea on how to determine which for which segment. I have a logic probe and a DMM on hand.
Would the fast mooving and dim back board chase lights be due to a weakened capacitor?
Seeing how none of the poppers what to work and only light up I can't imagine all their driver boards are bad and they do have the needed coil voltage available. I just assumed the poper contact came in and fired the individual driver boards.
The missing scoring of targets is a function of the Driver Board? Any idea of the mapping so that I can replace the needed chip &/or transistor.
Are the sounds driven by the sound board alone or is the driver board involved as well?

Thanks for your help. Lots to consider. - Tom

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I found a couple of videos that were both a good review and took me further.

Logic Probe

CPU Logic Basics

While looking for a 1982 Gottlieb Parts Catolog PDF on line I found a 1978 if anyone needs one. My surch continues...

gottlieb-1978-parts-catalog

https://vdocuments.mx/download/?url=79f1b83d35e30e1233c70e6619cb702e673acc6497650c489718e0a2e66faeffd86b71f25a0b2a5534bc8707e24718998eb4037d6fbabc02d808ca9c237ce1d6u2WSvERJGDsB3GcVTOQFEPkBlEonx3a/rd3bcI76vAxdCJGF42HG0l1Ypu8R2DaJKBzKoGW4TtxyBdXL9lshFw==

Black Hole is a System 80 just like yours. I ordered some checks so I can again do business with Steve Young’s PBR.

I have made a lot of progress. Mostly with Transistors and edge connectors. The three glaring issues at present are the displays, the poppers and one of the lower play field drop targets won't reset.

The displays malfunction in pairs so I'm assuming this is some failed chips. I need to see which ones those are and how to check them with a logic probe.

The poppers, I jumped the ground from each popper driver board connector and placed it on the Transistor case the it fires. So the ground and voltage is present yet the board doesn't fire on its own when the popper contact is closed. I need to look at the print for this and figure where the failure is seeing none of the poppers function.

The drop targets not resetting are the yellow ones on the lower play-field. They reset fine yesterday. I grounded its transistor on the main driver board and it works fine but will not reset on its own. I need to understand what tells it to use the reset coil.

In the meanwhile I wanted to get back after those mising digits on the displays. I replaced 7448's, Z19, Z21, Z23. I have a lingering problems on the bonus display for the lower playfield and the indicator 4 digit display. They are both missing segment C on numbers 3 and 7 only. Anyone know if this could be an issue with Z22, a 74175?