Since it's been so long since I've given this amp any attention, I thought I'd start a new thread as it's time to (really) start working on it. I've become a little more methodical over the past several years doing recaps and some troubleshooting, so this hopefully won't be quite the stab-in-the-dark restoration that I originally posted about here.
I've finished up a couple other long term projects and now it's time for this one. From the other thread I knew that the preamp functions worked but wasn't too sure about doing other testing, i.e. removing OPTs and powering up, etc. Well tonight I decided to put it on my work table and check the outputs. The left channel 2SB555 is toast: OL on both b,e and b,c as well as all other combos except c,e where it read 1.377V.
The R side OPTs checked fine, as well as the L Channel 2SD425.
So, 1st question regards a new mouser (or other order):
Since the recommended replacements are MJ21193/4G, should I just go ahead and replace all 4 OPTs with these, or just get replacements for the L side (i.e. would there be issues if the R side was originals and the L side new)?
If I should go ahead and replace all 4 (my current thinking) do I need to order several of each to try and match, or just get 2 of each and hope for the best (or find a company that does matched pairs)?
If I should get extras for matching purposes, what other amps could use these as replacements since I don't do this for a living, and the extras could well likely go unused unless I sell them?
What testing could I do in the meantime? Pull the outputs, reconnect disconnected boards, and see if it'll come out of protection?
Thanks for you're thoughts.
I've finished up a couple other long term projects and now it's time for this one. From the other thread I knew that the preamp functions worked but wasn't too sure about doing other testing, i.e. removing OPTs and powering up, etc. Well tonight I decided to put it on my work table and check the outputs. The left channel 2SB555 is toast: OL on both b,e and b,c as well as all other combos except c,e where it read 1.377V.
The R side OPTs checked fine, as well as the L Channel 2SD425.
So, 1st question regards a new mouser (or other order):
Since the recommended replacements are MJ21193/4G, should I just go ahead and replace all 4 OPTs with these, or just get replacements for the L side (i.e. would there be issues if the R side was originals and the L side new)?
If I should go ahead and replace all 4 (my current thinking) do I need to order several of each to try and match, or just get 2 of each and hope for the best (or find a company that does matched pairs)?
If I should get extras for matching purposes, what other amps could use these as replacements since I don't do this for a living, and the extras could well likely go unused unless I sell them?
What testing could I do in the meantime? Pull the outputs, reconnect disconnected boards, and see if it'll come out of protection?
Thanks for you're thoughts.