The 2x 10mA tunnel diodes in my 547 are dead (D45 & D245). While they were still in circuit, the -150V was perfectly dead on.
I replaced R703 and R705 in the power supply that had drifted and were badly cracked. One was 42R and the other 34R.
I removed the two TD¡¯s until I receive those I ordered (10mA also). However, now I¡¯m getting -187VDC and some change, and it¡¯s barely adjustable. Is that related to the 2 TD¡¯s not being present? At this point I didn¡¯t do anything else other than what I wrote previously.
Before you ask, I that I did follow the required settings on the scope. But I do not have a TU-77, just the 1A1 that came with it (the version with Nuvistors). Channel 1 is not functioning properly, but that¡¯ll be the subject for another thread.
BTW, the scope was somewhat functioning, but was only triggering with an external trigger, except for square waves that were more less stable without ext trigger. It was impossible to trigger on sine or triangular wave forms without an ext trigger.
A little background. The scope has been entirely cleaned and recapped. The fan has been removed, cleaned, and lubricated, and a new air filter has been added. Also, 3 transistors were bad in the vertical amp. They have been replaced with pairs as close as I could make them. One 6080 was also broken (V707), and has been replaced with a brand new one. It¡¯s the one the 2 cracked resistors above are connected to.
Any suggestions will be appreciated. I¡¯ve never worked on one of these before.
Thank you.
