Hi, all.

Just something I wanted to get off my chest.

Rant mode ON:

Why do the Data East/System 11 power supplies have to be so friggin' difficult. Is it too much to ask for a friggin' +5 Volts!

I've basically rebuilt the whole thing ( sans a couple capacitors ) and still 3.0volts at the +5v test point. Followed Clay's guide to the "T". Here what I've replaced so far:

+100v and -100v high voltage sections completely rebuilt - test fine, 2N60__ whatever transistor - tried 3 different ones, new DB1 bridge rectifier, IC replaced with added socket, mods done etc. etc. I'm into this for about $50 in components plus countless hours reading the guide and actually replacing those parts.

Finally I see Rottendog Amusements has a complete replacement for $75..... I want to puke.

Rant mode OFF.

Actually I've always found them to be easy to work on - about as easy as it gets!!!

Did you follow proper troubleshooting etiquette??

1: Isolate the suspected problem part (unplug EVERYTHING from the PS board expect the AC power IN)
2: Check for proper AC voltage IN.
3: Check voltages at all the steps (pre-BR, post BR, post filter cap, voltage regulator, etc.)
4: This should help you isolate the faulty component.


#1 is important because your low voltage could be caused by a ground short on another board.

Mike

Replace C2 & C3 ... especially C2.
These are the small capacitors that people usually disregard ... but they are very important to 5v regulation.

If it is not C2, C3, there is a Diode in that circuitry that I also found to be bad on a board I've repaired.  Don't give up, save the $75....

Thanks guys. I'll try some other things.... the capacitors seem to be all that's left to change. I'll also check those diodes. I'll keep you posted.

Dan

P.S. Mike, I have everything off the PS, only the AC in was connected. I'm going to assume that the AC voltage in is fine as I have my +100v and -100v for the displays. Plus my -12v and +12v checks out as well.

Most of the time when 5 vdc  is too low on these , you MUST replaced the small capacitors !!!!!

High voltage part of it has nothing to do with the 5 Vdc , it does not even use the same transfo winding !!!

Anyone have the specs of C2, C3 and the Diode? I want to stop by Sayal on the way home

C2: 100uF, 25V
C3: 47uF, 25V
Diodes, 1N4001 or any 1n400x series

I've got all the parts ready to go. Thanks for the info!
I'm just about up to the 75 bucks for a new one now.

I'll do the job Tuesday night after work and let you know how it goes....

Dan

I got a DE SW in my garage that just turns on, no dmd and its frozen no driver board lights either. Did all the BR's rebuilt power section still nada. PITA DE  

Quoted from mark

I got a DE SW in my garage that just turns on, no dmd and its frozen no driver board lights either. Did all the BR's rebuilt power section still nada. PITA DE  

Hey I'll trade ya for a fully working Laser Ball!!   I could even include a VERY partially working 6MDM

Mike

Well, although I purchased all the capacitors, C2 and C3 did the job. Now testing A-OK.

I have one issue though. The original C3 cap that I removed from the power supply was rated at 63v and not 25v ( as per Clay's guide ). I wonder if this is a typo as the schematic diagram shows 63v in this section as well.

Any comments?

Dan

P.S. Thanks for the tips everyone, this turned out to be quite an experience, Maaca members to the rescue yet again!