nakdoc from the music city

[nakdoc]

Hello all. I am a veteran of Tapeheads.net and a few other forums, and I specialize in repair and service issues. I've owned a small hi-fi service business for 40 years, and even though I plan to retire mid-2021, I always look for special interest groups focused on stereo equipment. I found this board while seeking information on a humming PV-2. The unit is so old the filter cap labels have faded ink! I specialize in tape decks, but also love tubes, high end audio, and the classic sold state stuff. My place here ought to be a stereo museum. Once approved, I'll post some interesting pictures.
I am not a "mod" happy expert, so feel free to ask for technical advice. You won't get a sale pitch about expensive upgrades, etc. I will not be able to offer opinions of upgrades unless I've seen them on my bench. Right now I am un-modding a Marantz 8 which has drastic parts issues (power supply was moved to a separate chassis), so you see I do run into adventures here at my shop. Hi Tech Service is located in Nashville, TN, and has been around since 1984.

[admin]

Welcome to the site. It's great to have you with us. I've approved your account so you are free to post anything you want.

We do have the PV-2 schematic in our database so you may want to download that to help troubleshoot any problems with the PV-2 unit you have.

I would love to see some pictures of your vintage gear or current stereo setup.

Again, welcome to CJO.

[roberto]

Hola and welcome,

Humming tells me that you might have a problem at the regulation stage...check the transistors, one might be open or short. It is wise to change all of them, not so expensive and the zener diode too. (This array is typically used on CJ, I do not know if the PV-2 uses...but I really think it does.

Please tell us your findings,

Happy listening!

[nakdoc]

The problem was low value can capacitor 50-80 uf at 500 volt. I replaced it with a pair of 47 uF 500 volt caps installed in the same area. I could have put them underneath and kept the can for looks, but this area is out of sight with the cover on. I was thinking this was a PV-2a because it has the 12 volt heater regulator. As a service guy I admire how you can open the preamp like a clamshell to work on it from the bottom of the board. It is no wonder this basic case design lasted for 30 years.

[nakdoc]

Am I member # 2000?

[admin]

Am I member # 2000?

I think #2046,... but that doesn't make you any less special.

[roberto]

The problem was low value can capacitor 50-80 uf at 500 volt. I replaced it with a pair of 47 uF 500 volt caps installed in the same area. I could have put them underneath and kept the can for looks, but this area is out of sight with the cover on. I was thinking this was a PV-2a because it has the 12 volt heater regulator. As a service guy I admire how you can open the preamp like a clamshell to work on it from the bottom of the board. It is no wonder this basic case design lasted for 30 years.

Good to know. This makes a lot of sense too. That was going to be my second guess. Great job! Also, Conrad Johnson has the same value caps.

Happy listening!