Altec 9470A / 9475A rack-up

[Whoops]

Whoops, What was your method for removing the metal shield caps from the Q1-2 and 3-4 pairs?  Mine are jammed on really tight

Metal Shield caps?
can you post a photo?

 

[emrr]

sounds like the early ones that are transistor pairs in one case?

 

[lassoharp]

sounds like the early ones that are transistor pairs in one case?

Ah, maybe that's it.  I didn't realize it was actually a case.  I saw the pic Whoops had posted with the visible xsistors and thought he'd removed a shield.

 

[lassoharp]

Metal Shield caps?
can you post a photo?

 

[emrr]

Yeah those are the duals.  One of the two schematics out there is for that version, not really any different but different part #s listed. 

 

[lassoharp]

Here's a pic of the incorrect R11 that ended up in one of mine.  R11 should be 220K and not 2.2M. 

This unit had the 22R PSU resistor completely burnt and it also took out both 3053s in the output circuit.   

I put a meter across the OT pri and measured about 1.4 ohms (should be 28 ohms).  It had shorted collector to emitter in both 3053s.

Appears to be another grounding disaster!

 

[Whoops]

Hi lassoharp,
my modules didnt have that metal shield, they were already like you can see in my photos.

I never had seen your transistors version before or I didnt noticed it before

best regards