|
Vintage Asylum Classic gear from yesteryear; vintage audio standing the test of time. |
|
|
|
Vintage Asylum Classic gear from yesteryear; vintage audio standing the test of time. |
|
Hi,
today a friend came to my home while I was taking some voltage measures in my Sherwood S-5000. We were talking about the hot bias it had (-13 instead of -20) and about a resistor I had to replace maybe together with the selenium rectifier. When I was in another room, he took my digital meter, turned it into the ampere position and tried to "measure" the Amperes that were coming out from the selenium rectifier, but he did this in the wrong way, by using the meter as it was a voltmeter, with a plug into chassis (ground) and the other on the + of the rectifier. Some little sparkles came from the point where the plug touched the rectifier, with some pops. In the meantime I returned and immediately stopped him, but the damage was done. Now the amp has a big hum, and the music from a CD player is low. I tried to measure some voltage but now everything is messed up. The output tubes have 240V plate instead of the 380 that they had yesterday, the bias is non-existing (+3V istead of -13), and I turned all off to avoid other damages. I checked the 12ax7 tubes (that are feeded by the rectifier current) with my tube tester and they seem still all fine.
Now I have to find a technician here that can take a look at it (but in my area there are no good techs that I am aware of).
I think that at least one big capacitor (C3 that was connected to the selenium rectifier) is surely gone to create such a hum, but I don't know if there is some more possible damage (other filter caps?the secondary of the power transformer?). Can a failing filter capacitor explain all that mess?
Any advice? I can email a rather good schematics including the power supply stage if someone is interested. That C3 capacitor is: 150 - 250 - 50uf at 50V
Thanks
Raul
This post is made possible by the generous support of people like you and our sponsors:
Topic - A friend just shorted my Sherwood S-5000! - Raver 11:48:39 12/29/03 (21)
- SOLVED, IT WORKS OK NOW! - Raver 10:26:17 12/31/03 (0)
- Re: A friend just shorted my Sherwood S-5000! - merccougar89 22:15:45 12/29/03 (0)
- Re: A friend just shorted my Sherwood S-5000! - Jimmy 15:03:57 12/29/03 (0)
- Re: That's nothing compared to what your Asylum friends can teach you to do:) - Russ57 12:48:56 12/29/03 (11)
- Which caps must I use to replace the can filter caps? - Raver 13:49:13 12/29/03 (0)
- Re: That's nothing compared to what your Asylum friends can teach you to do:) - Raver 12:56:43 12/29/03 (9)
- Re: Looks like you need.... - Russ57 06:30:05 12/30/03 (8)
- And what about the third multi-cap? - Raver 06:49:45 12/30/03 (7)
- Re: Caution! - Russ57 11:29:40 12/30/03 (6)
- Re: Caution! - Raver 12:04:20 12/30/03 (5)
- I just realized I have a wrong schematics! - Raver 14:59:00 12/30/03 (4)
- That's it, you didn't read very carefully on my listing below for diodes - koo 16:25:43 12/30/03 (3)
- Re: That's it, you didn't read very carefully on my listing below for diodes - Raver 01:51:52 12/31/03 (0)
- Re: That's it, you didn't read very carefully on my listing below for diodes - Raver 01:50:45 12/31/03 (1)
- My apology too, being too assertive, just want to make things right - koo 16:32:15 01/01/04 (0)
- Re: A friend just shorted my Sherwood S-5000! - budm 12:24:20 12/29/03 (0)
- Re: A friend just shorted my Sherwood S-5000! - Jim McShane 12:15:28 12/29/03 (4)
- Re: A friend just shorted my Sherwood S-5000! - Raver 12:51:35 12/29/03 (3)
- Better say, the line-marks on diodes should point at transformer(nt) - Koo 23:33:24 12/29/03 (0)
- Read the schematics, it's centre tap in bias circuit, two diodes OK BUT - koo 23:28:55 12/29/03 (0)
- Double posting, see my comments on tube asylum. Don't think it's OK - koo 23:15:07 12/29/03 (0)
Top of Page ]
[ Contact Us ]
[ Support/Wish List ]
[ Copyright © 2024, Audio Asylum, all rights reserved ]
