|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
||Thread Tools||Search this Thread|
|27th May 2006, 08:02 PM||#1|
Join Date: Mar 2006
Location: Sheffield, England
Help with repair of Marantz PM17 KI please
I was hoping I could get some help with repairing my Marantz.
A few weeks ago I decided to "tweak" the bias current on this amp (Why didn't I leave it alone?) and in the process blew the two power transistors on the left channel.
I have replaced all transistors on the left channel (I am waiting for the 2SC3419 to turn up). I also replaced three low-value resistors that had blown. I got a copy of the service manual and checked all resistors as well. BUT I came to check the B-E resistance on the transistors to compare them with the good channel and some are way off (The A1303's are nearest the HDAMs):
Tran. L R (kOhms)
1303 3.14 3.53
1837 3.77 3.74
3419 2.01 2.01
4793 5.24 5.26
3284 3.03 3.73
I set the left trimmer to the same value as the right channel (about 1.3k)
Here is a picture of the boards:
Any ideas what I need to do to get the resistances for the two main power trannies correct? Any other advice about my problem?
If I have changed the transistors on one side only will it affect the sound of the amp? Or is it best to just get another board altogether? Marantz quoted £240 to replace the board but apparently its £90 just for the part.
|29th January 2007, 08:10 AM||#3|
Join Date: Nov 2006
Hello, if you change the output transistors with a good type (sanken!) I think will be the right way (pay attenction to the counterfeits transistors labelled like originals...). You have to make a bias correction, so I think that maybe dangerous.
Often when you turn the bias trimmer a little, the bias current increase much much more, you must pay attenction, you must have a digital multimeter (two are better) for checking the incoming currents.
I don't know if Marantz on pm 17 kis select output devices strongly. You can try to change the defective couple only and (after the regulations and few hours of works) make a listening check.
Can you send me a copy of service manual at my e-mail address (I'm waiting for a defective pm 17) ?
|Thread Tools||Search this Thread|
|Thread||Thread Starter||Forum||Replies||Last Post|
|Marantz CD63 Repair||big jim||Digital Source||1||23rd August 2014 02:51 PM|
|Marantz 250M Repair||PB2||Solid State||49||11th January 2012 05:09 AM|
|Help Need To Repair Marantz Pm 94 Class A Amp||seafire||Solid State||18||23rd November 2009 08:47 AM|
|Marantz PM-17 repair||hirafu_boarder||Solid State||0||20th July 2007 01:25 PM|
|Peculiarity in Marantz PM17 schematics||ergo||Solid State||4||10th January 2002 11:32 PM|
|New To Site?||Need Help?|