M-80 Restore

[avionic]

d found 6.3volts 220uF replacement

I use polar 220µf@10vdc.. Just like the OEM parts.. Only bi-polar I use is the 47µf@25vdc

 

[avionic]

'0.2L/S' '5x11 20% 2LS' ?

LS lead spacing in mm
5X11 physical dimension in mm.

 

[Soundscape]

I'm about to stock up on caps from MOUSER for winter hobby work / future use. My serviced M-80 works fine for now with the original main filter caps. But someday I'll wanna replace them. The hood is on and jamming in the rack so I don't have mm measurements.
Looks like two 45000uF 45V & two 33000 56V. Got any recommended replacements? Hoping someone had recent experience with this and had part#'s written on their hand or something, lol. Are these a bitch to find?

 

[whoaru99]

Yeah, early in the thread goes through some of that stuff.

 

[Asmodeus2112]

I'm about to stock up on caps from MOUSER for winter hobby work / future use. My serviced M-80 works fine for now with the original main filter caps. But someday I'll wanna replace them. The hood is on and jamming in the rack so I don't have mm measurements.
Looks like two 45000uF 45V & two 33000 56V. Got any recommended replacements? Hoping someone had recent experience with this and had part#'s written on their hand or something, lol. Are these a bitch to find?
View attachment 3837956

I have replaced these on two M-80's right now. They are doing fine, but I have been thinking about a better way. I'd like to design a new board that the main filter caps reside on and change the caps to several smaller modern form factor caps in parallel. Then 3d print a new mounting bracket. This area is a PITA on the M-80's.

 

[Arc deTriamp]

Agreed if installing a polar 100µF cap is the choice. I think the safer and more accepted route is to install the bipolar. To tell you the truth I already installed a UES in that position because I have those in stock, but that could easily be reversed.

I would like to understand the polarity of C164 just to be complete.

Couple of things. The zener diode paralleling C164 is reverse biased and provides a drop of about 17v. The PCB silkscreen for C164 has incorrect (backwards) polarity. Most people use a bipolar because of the confusion.
Regarding “fusible” or flameproof resistors on the M-80:

R222 and R221 carry the +/-HB for the IPS and the VAS, everything up to pre-driver transistors, but most significantly the current to charge up 1000uF C162 and C163. Although they ordinarily carry a small current, at power-on these 1/4W resistors must withstand up to 18W, (0.9A) momentarily! In my experience, the FRN series resistors will consistently fail at startup unless you are using a DBT. But, the Stackpole CF series (CF14JT22R0 in this case) work fine.