Philco C7542BPC (3CY91 chassis) console

[zeno]

Originally Posted by rca2000

I STILL wonder...how the "old school techs"...handled the JA power supply...back "in the day" Today--it looks a LOT like a typical chopper SMPS--which is VERY familiar..but when it was in CURRENT production? I would guess it gave a LOT of headaches !!

Ah yes the JA. First one I saw I didnt get at all. Showed the boss
the Sams & he said " buy a Fing board. I have NO idea how this
works". Had I continued I am sure I would have called Moto
for help. They would say " why dont you buy a Fing board. We
use modules for you ! "
Back then there were just a few killer sets.
1) Sony SG613 sets
2) JA Motos
3) RCA SCR sets
4) how to keep a sears Warwick SS chassis running !
Specialist got the Sony work, dont leave mad just leave !
Motos plugged on, not many anyhows.
RCA SCR sets were reliable & predictable.
Sears Warwick SS "take it to sears" followed by tears from customer.

73 Zeno stuck in the past.

[rca2000]

I STILL would rather work n a JA module set.....than ANY SG_613 or such Sony NIGHTMARE. SMPS supplies are "old hat" to me by now--since EVERY flat-panel set uses them...I see a LOT of them..and usually have GREAT success fixing them. The JA is pretty normal in the SMPS design--other than the fact that is uses an NPN transistor for the Switch-out transistor instead of a MOSFET..as nearly ALL SMPS units do now.. And locking to the horiz. rate for SMPS operation was done in a lot of sets, during the CRT era..

But those Sony SG sets...HATED them.. You would spend a lot of time getting the horiz. ckt repaired..regulator replaced and such..power it up and BOOM !! ALL of it was gone in a quick FLASH. and I do NOT think a variac was of much help...either. And sometimes...they would work...and you would THINK all was well...and then BOOM.

Best thing for the SG sonys''....a packer truck !!