Hello Everyone. I have a System-1 story for you...

How many of you have done a re-cap, only to have something else go awry? I realize this stuff is nearly 40 years old, (me too, LOL) so maybe bad things do happen when you challenge Murphy's law?

I have a beautiful Genie. I put an entire weekend into cleaning, waxing, new rubber, replacing the MPU battery (with external AA holder/diode) and all the love I could give it. The game played great. Every single thing worked to perfection!

THEN...

I decided to re-cap the PSU! Now I'm stuck with a dead machine

After non-boot, (GI and sound board OK) I immediately powered down and removed the display and MPU cables from the PSU. All testing below is done without MPU/displays connected.

I checked all of my caps, they have the correct polarity and rating, there are no cold solder joints, etc. My heatsink-mounted transistors all got a fresh and even coat of thermal paste, and the micah insulators were checked for cracks, and found to be in spec. I am using plastic screw insulators for the two TO-3 packaged transistors that are mounted to the heat sink. I even put a fresh blob of solder on the two NPN pins on the top of PSU board, to ensure contact.

I'm getting the correct AC voltages from the transformer to the PSU, and yes, my Molex pins are all making solid contact, and I'm careful to plug the connector in the right way, not upside down.

I verified that I have CORRECT voltages of +60vdc, +42vdc, +8vdc and -12vdc
I verified that I have INCORRECT 5vdc (reads 2.3vdc) and 4vdc (reads 1.2vdc)
I am aware of the separate grounds for 8/5/4 and 60/42 voltages, and tested appropriately.

I checked the darlington transistor and it appears to be OK, but I only did a diode test on E, B and C with my DMM.
[DMM in diode mode, +=red, -=black probe]
(E+, C- = 0.448)
(E-, C+ = OL)
(E+, B- = 2.38)*
(E-, B+ = 0.542)
(C+, B- = OL)
(C-, B+ = 0.533)
*There are added resistors inside the transistor package, so this should be a normal reading?

I pulled several diodes from the board and they all checked out OK, the two voltage adjustment potentiometers are working within specifications.

I have narrowed the issue down to the linear regulator (723H 10-pin TO-100) Because it provides a regulated base for both the 5 and 4 VDC circuits.

I have a new 723H on order (as well, a darlington NPN), but am wondering WHY the trouble? Was my regulator 'dying' and fresh capacitors just pushed it over the cliff?

I am also thinking of the 'crowbar' circuit, but have not investigated it, I assume the 5V output would be zero if the protection circuit is active?

BTW, I bought the caps as a new kit from GPE, but did not have a way to test them before installation.

Anyone have thoughts? I'm perplexed

I hope I can fix this soon. I love this machine.

From now on, maybe it's better to leave well alone... unless you have an on-board rechargeable MPU battery sitting there...

I checked everything under a magnifier. There doesn't appear to be any traces touching.

The photos show the NPN 5V transistor removed.

20161106_151355 (resized).jpg

20161106_151409 (resized).jpg

Grizlyrig, cap is ok it looks domed in the pic but it's normal. I will alcohol clean the bottom of board tomorrow and inspect further, but I checked continuity on adjacent traces and found noting unusual.

Forceflow, I have two pots on order along with beefier rectifier diodes. I bought a rebuild kit to get the two IC's, so the other parts are almost free of charge

I'll keep you all updated. I'm still miffed about the whole thing, has anyone had a component suffer after a re-cap?

Thanks

That's always an option...

After re reading Clay's System 1 guide, I spotted "2.4v output means q1 (Darlington NPN transistor) is bad"

Hoping this is the fix!

I'll update in a few days. Thanks everyone.

Hello G-P-E,

C6 looks worse in that photo than it really is, I should find a better way of testing capacitors other than the ohms test anyway. I have tested the 60 and 42VDC outputs with the trimmer pot and they look great. (C3 and C6 (all caps for that matter) are the correct values)

The issue I'm having is the 5V and 4V side of things. I don't know how, but I'm eager to find out why!

My parts won't be in for a few days either way. Once fixed, I'll find a parts PSU and fix that one, so I have a spare.

Yes, there are nice, aftermarket ones out there. They are better in many ways (run cooler, conserve power).

Something about fixing what I have first, then upgrade after the holidays perhaps (I have run out of pin-cash). This Genie has 100% original parts inside, the MPU and driver boards are immaculate. The Molex connectors are very strong electrically, this machine sat, protected for many years. If I ever sell it, I would put that original PSU back in

-UPDATE-
Replaced Q1 (NPN) and IC1 (5v reg)

Everything OK now