Opening emt 262 amp

[salomonander]

Ok, im too stupid to open this module up. Can anyone help me on how to proceed?
thanks!

 

[zamproject]

The obvious look like pulling-up pcb at connector side, and then slide it to the back out of the front forks...
But I suppose you already try this ?

I open once a 240, was long time ago and I don't remember if I pull-out the amp nor if I open the module

 

[zamproject]

from a 256 but should be the same

 

[salomonander]

Thanks mate. I tried this first but no luck. the lower side of the pcb slides easily, but its stuck on top and i dont want to apply force. Maybe one of the top screws needs loosening as well?

 

[zamproject]

mmm... don't seem you need to remove those three ?
What about the second pcb on the other side ? maybe you need to remove it first ?
The document I post show the module upside down according to bended bracket placement at the connector side.
Also it seem there is rubber washer between pcb and bended bracket, maybe they stick with the time ?

 

[salomonander]

Thanks mate… i removed the rubber washers. Ill just try around a bit. If anyone opened one of these up, please help

 

[zamproject]

Sorry to can't help more
PCB show no obvious extra screw or pcb mount connector/pot that can obstruct the pull out and I see no reason for fancy mechanical integration, especially concerning old german broadcast engineering where service should be easy...
I'll try to gently apply force, in case something get stuck by age deformation/dilatation, but it's not my module and I don't have it in hand to judge/feel how far I can go.
Someone else will chime in for sure !

Cheers
Zam

 

[abbey road d enfer]

I would ask one question. How is the front plate (that holds the potentiometers) affixed to the frame?

 

[zamproject]

@abbey road d enfer , I suspect it's a punch welding to close the frame U shape, if the idea is to loose it to have access and remove the pcb I'm afraid it's not possible (if my assumption is correct )

 

[salomonander]

Zamproject…. Thats how it looks like to me

 

[salomonander]

I was able to peek inside a bit more. Seems to me as if the three top screws are holding power transistors and at least one of them is soldered to the pcb but tightened with screw and nut. Impossible to reach. what were they thinking

 

[salomonander]

Ok, managed to get it open. this module is ridiculous. See attached pic. one has to desolder these two transistors. Now, i still cant work on this since the morons at emt made their connection cables so short, that i will have to desolder all cables in order to fold it open. I hate emt at this point - with passion

 

[zamproject]

Glad you find the way.
More tricky than expected. De-soldering component to extract a pcb is unusual and not that cleaver

 

[salomonander]

If you guys dont mind, i do have one more question:
my modules seem to be slightly modded. On each module there is one capacitor that is clearly newer and has a value of 22uf instead of 1uf. See attached schematic. Anyone have an idea if this makes any sense? i assume someone simply f*cked up as the capacitors position in the schematic is 221. so maybe someone just misread the position for the actual value…

 

[abbey road d enfer]

If you guys dont mind, i do have one more question:
my modules seem to be slightly modded. On each module there is one capacitor that is clearly newer and has a value of 22uf instead of 1uf. See attached schematic. Anyone have an idea if this makes any sense?

Looks like an attempt to increase the attack time of the expander, reason unknown.
Try replacing it with the original value and listen.

 

[zamproject]

Difficult to be sure why it was done, mistake or on purpose.
But for what I see it lower a lot the sidechain cutoff from 160 to 7Hz
So the VCA in the recovery amp should be more reactive to low frequency (expander)

 

[zamproject]

Hahaha... I'm probably wrong and abbey right

 

[salomonander]

Thanks guys, i think ill just put in the standard value.

 

[Bo Deadly]

Hahaha... I'm probably wrong and abbey right

Or you're both wrong?

22u would make it slower.

 

[abbey road d enfer]

22u would make it slower.

Isn't it what I suggested? Post #15...