Stax SRM-212 repair?

randomlf · 10:35 PM

Hi,

Just received this broken unit. Right channel works perfectly but left channel is cut out.

Do you have any suggestions what parts should I try to replace first?

Tried to search the web but couldn't find a service manual anywhere..

Here are pics for the amp:

randomlf · 21st December 2012, 10:33 PM

Any help would be appreciated, even if you don't have experience with this specific unit.

I don't understand anything about amplifiers, but I could solder new parts in it if I knew what was broken. Could someone help me troubleshoot the amp?

sgrossklass · 25th December 2012, 08:14 PM

ERR#900F: Pics no workee.

Still, I don't think it is advisable that you undertake a repair yourself, unless you happen to find a trivial fault like a bad solder joint at input or output jacks. Amplifiers like this typically operate on like +200..300VDC (plus there's the bias voltage of 580V), so all the usual safety precautions for tube gear apply.

Once power has been off for quite a while, you should be able to perform some basic in-circuit transistor testing, just making sure that none are dead short or open somewhere. If you are lucky, corresponding parts in the left and right channel are easily identified, so you can check whether measurements match.

randomlf · 10:34 PM

Quote:

Originally Posted by sgrossklass

ERR#900F: Pics no workee.

Still, I don't think it is advisable that you undertake a repair yourself, unless you happen to find a trivial fault like a bad solder joint at input or output jacks. Amplifiers like this typically operate on like +200..300VDC (plus there's the bias voltage of 580V), so all the usual safety precautions for tube gear apply.

Once power has been off for quite a while, you should be able to perform some basic in-circuit transistor testing, just making sure that none are dead short or open somewhere. If you are lucky, corresponding parts in the left and right channel are easily identified, so you can check whether measurements match.

Hi, the pics work when you right click them and "open up a in a new tab", at least in the two computers I tried to open them

I have an multimeter, but I'm not sure what I should measure, like I said I don't understand much about amps. Though the pcb has clear separate sections for right and left channel, so I could easily compare them measurements.

You can also PM me if you don't want to type here.

randomlf · 27th December 2012, 01:38 AM

So like you can see in the pictures, the unit has 8 leds inside the unit, and they all light up when the device is on. I think there's 4 leds for each channel. Could this mean that there's at least something working on the left side.. ?

chinsettawong · 27th December 2012, 05:03 AM

Can't see your pictures.

Wachara C.

randomlf · 28th December 2012, 05:42 AM

Quote:

Originally Posted by chinsettawong

Can't see your pictures.

Wachara C.

Hi, here are direct links to the pictures, just press them and you should be directed to the imageshack website.

ImageShack® - Online Photo and Video Hosting

ImageShack® - Online Photo and Video Hosting

ImageShack® - Online Photo and Video Hosting

ImageShack® - Online Photo and Video Hosting

20th December 2012, 01:08 AM	#1
randomlf diyAudio Member Join Date: May 2012	Stax SRM-212 repair? Hi, Just received this broken unit. Right channel works perfectly but left channel is cut out. Do you have any suggestions what parts should I try to replace first? Tried to search the web but couldn't find a service manual anywhere.. Here are pics for the amp: Last edited by randomlf; 21st December 2012 at 10:35 PM.

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21st December 2012, 10:33 PM	#2
randomlf diyAudio Member Join Date: May 2012	Any help would be appreciated, even if you don't have experience with this specific unit. I don't understand anything about amplifiers, but I could solder new parts in it if I knew what was broken. Could someone help me troubleshoot the amp?

25th December 2012, 08:14 PM	#3
sgrossklass diyAudio Member Join Date: Nov 2004 Location: Germany	ERR#900F: Pics no workee. Still, I don't think it is advisable that you undertake a repair yourself, unless you happen to find a trivial fault like a bad solder joint at input or output jacks. Amplifiers like this typically operate on like +200..300VDC (plus there's the bias voltage of 580V), so all the usual safety precautions for tube gear apply. Once power has been off for quite a while, you should be able to perform some basic in-circuit transistor testing, just making sure that none are dead short or open somewhere. If you are lucky, corresponding parts in the left and right channel are easily identified, so you can check whether measurements match.

27th December 2012, 01:38 AM	#5
randomlf diyAudio Member Join Date: May 2012	So like you can see in the pictures, the unit has 8 leds inside the unit, and they all light up when the device is on. I think there's 4 leds for each channel. Could this mean that there's at least something working on the left side.. ?

27th December 2012, 05:03 AM	#6
chinsettawong diyAudio Member Join Date: Jun 2006	Can't see your pictures. Wachara C.