Recent content by david winter

FYI, I've been servicing vintage hifi (including Revox) gear for almost 20 years. I tested all transistors on that board before considering replacing them, and always test transistors before installing (I have three different testers including a Peak DCA Pro 75). It's just that the 2N3441 turned...

I finished realizing that I got misinformed by some web site giving the 2N3441 as cross-reference for the RCA 40318 (whih was open). As the 2N3441 didn't work (it even developed a c/e leak), and as I didn't have the proper replacement transistor, I picked another board in a A77 kept for spares...

Hi, I'm trying to find why this A77 MK2 has its capstan motor spining at maximum speed. The main psu has been restored and the +21V is ok. The capstan board has been checked as follows: - Electrolytics replaced as usual. No polarity errors, no wrong values. - RCA 40318 transistor found open. I...

Hi, I need to repair the CPU board which is revision 12. It has a few changes, one of which is the addition of a LM393 to the circuit enabling the electromagnet (driven by the BD679). All the schematics I found so far correspond to the previous version without the LM393. Another unit in my...

Hi, I'm trying to figure out the possible cause this problem after doing the following: - Full recap of the cpu board - Full recap and rechip of the motor daughter board (all CMOS chips tested bad with my TL866-II). - Replaced Q17 (BD679) which I suspected to be bad (didn't test well) but no...

Hi, I need to replace the idler tires in a Sony TD 152 SD. Anybody knows the model to use ? It's not just a matter of height, but also diameter to ensure proper friction against the pulleys. I don't know if the TC 153 and TC 154 share the same rubber rings. Thanks !

Thanks for your hints. I bought a belt from yomusic on the bay (from Bulgaria). Works great, didn't even have to adjust tape speed.

Hi, Somebody brought a faulty Teac A-3440 to me. I had to rebuild the power supply board and fix the capstan servo motor board as well. The guy put a new belt but I have no idea where it comes from. However, I think it's not appropriate as it always swings on the motor pulley when the motor...

Hi, I'm stuck and trying to understand the cause of the following problem: I have a Revox B215 which stops randomy in FF / REV modes. So far I did the following: - Recaping the power supply / control board (the one with the three MAB 8440 chips) - Recaping the daughter board (capstan driver) -...

Hi, I hope this post fits the forum. I'm asking this to improve some of my measuring equipment as actual gear is a lot easier to handle (LCD screens, exact frequency setting, precise counter, etc). I would like to find a function generator which also serves as frequency counter, which has good...

I found a Bernstein 2-305. Thanks for your hints.

Hi, I'm interested in buying a Nakamichi T-100 audio analyzer (european version only, so not the 120V one). Thanks !

Thanks. Unfortunately they don't seem to have it (I searched for Bernstein to see all items but didn't get the 2-305).

Hi, I'm looking for a Bernstein 2-305 demagnetizer (220V) which I find quite convenient. Handy, and the core is not the thin type I often see. Unless you don't recommend using this mode for any reason... Any info welcome. Thanks !

Hi, I can't really help you but here are the causes of motor failure that I encountered so far: - Bad relay contats (seen in A77; don't know if the PR99 has the same relay commands) - Bad motor capacitors (the cylindrical ones mounted on the chassis) - Bad motor "switch" capacitors (usually...