Go Back   Home > Forums > Amplifiers > Solid State

Solid State Talk all about solid state amplification.

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 23rd October 2010, 06:48 PM   #1
tchiwam is offline tchiwam  Finland
diyAudio Member
 
Join Date: Sep 2010
Location: Lapland, Finland
Default Marantz 2235B with high pitched noise ...

I have a strange one here ...

Found the schematics from this guy Home - IRebuildMarantz. Really nice reference but I don't agree on the list of capacitors to change ...

Anyway, I have now changed a lot of capacitors, all except the "tantal" looking ones. Readjusted the Biases to 0VDC, 35VDC rail from the PSU board and 8mVDC from the power amp. Then cleaned all the pots.

Here is the problem: High pitch noise on BOTH channels I'd say around 15 to 18kHz, really annoying.

It is there on all positions except when on Phono ! I can even run a line in in the Tape 1 Monitor and there is NO noise.

AM / FM / AUX / TAPE 2 IN all of them have the high pitch noise...

The noise was there before and after the recap.

I think I can rules out the Power amp board it has such a great sound on Phono + Tape 1 Monitor.

The tone board is probably ok too, as it is on use with the Phono switch with ou without the Tape 1 Mon.

I don't want to touch the AM and FM section...

I am now leaning on checking the phono board as if it is not used it might do something funny. But the power is permanent on that board as seen on the schematics. The outputs are disconnected... Unloaded lines make noise on the power line ?

I'll get my Osciloscope and try to get that one out. But if anyone is able to pin point me to the solution I'd be grateful.

Philippe
  Reply With Quote
Old 23rd October 2010, 09:06 PM   #2
diyAudio Member
 
Join Date: Mar 2010
You are on the right track. It definitely is a job for an oscilloscope. Identify the waveshape, probe around to find where its amplitude is greatest, look for a bad ground somewhere.
  Reply With Quote
Old 31st October 2010, 03:43 PM   #3
tchiwam is offline tchiwam  Finland
diyAudio Member
 
Join Date: Sep 2010
Location: Lapland, Finland
Default Got the devil !

One of the new cap on the phono amp missed a leg, and I also noticed a cold joint on the board. That is fixed too.

Now I have to say the AMP is running hot, I have adjusted the voltages, bias and all but no avail yet, still hot. I guess I need to change some semi conductor on the PSU like some other thread mentioned.

Sounds good and it can be really loud and clear.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Gainclone picking up buzz/whine/high pitched noise from TV power supply altie Chip Amps 3 5th July 2010 12:10 PM
high pitched noise candyman122 Car Audio 7 7th January 2010 02:13 AM
$300 speakers to pair with Marantz 2235B? mminutel Multi-Way 1 24th December 2009 04:32 AM
Marantz 2235B Tuner Issue??? mikje Solid State 11 6th July 2009 02:00 PM
Marantz 2235B running hot mikje Solid State 12 9th March 2009 07:20 AM


New To Site? Need Help?

All times are GMT. The time now is 03:48 AM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2