Got a couple questions.

So, I've decided to try my hand at recapping (and replacing two diodes), seeing as I have something old and worn out to work on. But before I start, I need to be clear on a few concepts.

If anyone has a schematic, preferbly not for a clone, I would greatly appreciate it.


First, is there a difference between (V) voltage and WV (what I assume to be Working Voltage)? I have a bunch of caps in a Martel FAX-200, some just have V, others have WV on them. (150V, and 400WV, respectively)


Second. Some of these caps, which are small axial electrolytics, have uF (10uf, .001uf, .05uf) on them. Others, which are electrolytics, have MFD (these are the size of a half of a roll of pennies, and say 20MFD and 40MFD) printed on them. Shall I assume that uF means the same thing as MFD, as opposed to MFD being millifarads, or megafarads or something else?


Third, from what I read, it's OK to replace say, a 40uf at 150V capacitor with a 47uF @ 160V capacitor. But unless I shop at many different places, I simply cannot match every unit in here for an original. Will it do more harm than good to have every cap slightly above spec?


Fourth. I want to go ahead and replace the old rectifier diodes, which there are only two of. The most common one tossed around here seems to be the 1N4007, rated for 1A. In the apparantly unlikely even these are not available, Would putting anything else, like on rated for 2A work, or would that allow too much current on the circuit?

Thanks in advance.

All that is correct and fine to do.

Rod, It sounds like the 40uf to 47uf situation isn't an issue for you but if the cap were one where the value was critical you can combine caps in parallel to get to the needed value. For example if you had two 16uf and an 8uf in parallel it can get you to 40uf. Of course you get into space considerations, etc.

Jay, AK search says you worked on one of these Martel FAX-200 receivers back in 2006. Even saw where you were trying to dig up a schematic over on AudioAsylum. Funny what turns up some times.

Cool, ya sure don't see or even hear of these old Martel tubed units very often. :thmbsp: I have the FAX-100, a SE 6BQ5 receiver.

Edit: Hurr hurr hurr I reed gud lol.

Did that schematic ever get found? There was a similar one posted for a Kenwood, but I couldn't figure out the preamp section, which seemed to only have two 12Ax7s as opposed to three.