Melos MA-222 Tube Preamp info needed

Gepetto said:
Looks pretty basic Perry.
Click to expand...

Now if I can figure out the voltages which are fed to the pre-amp box. Plus not knowing the output of the transformers makes it difficult. I suppose I could hook the transformer(s) up to 120vac and see what the pairs of windings are putting out. Without a load on the system it may not give me the info I need.

I know that we can use 6.3AC/or DC for the filament/heater

B+ can be +130VDC for the 6GK5 Phono tube
B+ can be +250VDC for the 6922 Triode tube

I think I saw a PS that is adjustable from 100VDC to 300VDC and 6.3 outputs so it might be doable.

HUH?????
 
I guess I should just pull the PS board and make my own skizmo.....

I have a couple (2 on each side) unmarked Zener Diodes that I'll have to figure out what the hell they are. They are in the regulator circuit and marked

Motorola SZP 401 82 8240 which MAY be a part Melos had custom marked (???). They are in the TL783 regulator circuit (for short protection) and can they be deleted??? OR???
 
WOPL Sniffer said:
I guess I should just pull the PS board and make my own skizmo.....

I have a couple (2 on each side) unmarked Zener Diodes that I'll have to figure out what the hell they are. They are in the regulator circuit and marked

Motorola SZP 401 82 8240 which MAY be a part Melos had custom marked (???). They are in the TL783 regulator circuit (for short protection) and can they be deleted??? OR???
Click to expand...
No way custom made Perry
 
Gepetto said:
More likely they picked up some surplus from Fry's electronics and used them by the looks of that assembly. :)
Click to expand...


I wouldn't doubt that. Any way to ID them if I have the one side of the PS up and running or by seeing how they had it in the circuit with the resistor?
 
If there is a maker name and part number on the transformers you might find it’s designed specs…
 
Okay, this is just the power supply. I was having trouble locating the tube sockets…
 
I'm going through 800 pages of Motorola diodes

It says:
SZP
401
82
8240

It appears to be a zener but I aint finding shit
 
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