advertisement


Hi Fi Repairer

Hmm You have two phono stages that had the same hum problem appear at the same time? If that happened to me I'd suspect the TT/arm/lead/earth had developed a problem maybe a lead has come adrift.

The high price of repair tells me that the manufacturer doesn't want/have a service department and rather than spend time trouble shooting would maybe just replace the innards with new parts.

You then get it home and still have hum...........

Cheers,

DV
 
Thank you all for the suggestions . As stated earlier no problem running through 32.5 Naim cards . Have already checked for shorts and continuity on arm leads .
Yes you are right, when i spoke to Whest before taking the phono stage in they stated that they very rarely repair anything at base but would have a look ,which leads me to think they would just change the board for a refurbed one . This might explain only a 3 month warranty . The Unison Research is a recently acquired used one and i only pressed it into service in place of the Naim system a few days ago and did not notice any buzzing through the phono stage input at first, i therefore cant be certain whether i caused the problem myself. I have read stories of static discharge causing damage to phono stages but users here in the know find that very doubtful and they are probably right. Maybe i have just been unlucky and a victim of coincidence . Not to bothered about the Unison research as it sounds excellent on all other inputs and i got it for a reasonable price which would allow me to have it repaired and serviced at the same time and it still would have been a
good buy considering the price new .
 
I had been running the Whest into the tuner input on the 32.5 for a very long time before the problem occurred . Now running the linn into the phono input on the 32.5 and all is good . The unison research integrated has a phono input which now has the problem and never been anywhere near the Naim pre .
 
sq225917 said:
The red box is a new addition, old boards just had opamp and a few resistors in that area.

Probably just a cover.

http://farm7.static.flickr.com/6060/6249494832_6fefb084ce_b.jpg
Click to expand...

If anyone is feeling brave then epoxy potted modules can be unpotted with dichloromethane. I am surprised the manufacturer wants so much to fix it, given phono stages don’t exactly lead stressful lives and modern components are usually very reliable my guess is it’s a manufacturing defect, most likely a dry joint, and thought they would be keen to find out what it is and generate maybe a bit of good will by not charging silly money for something that shouldn’t take them long to find and almost certainly won’t cost much to fix.
 
I'm with GT here, it's next to impossible that it's an electronics fault affecting two phono stages. It's likely to be a system fault.
 
Whatever the fault..whether it is in the phono stages or not. £650 is taking the piss. I have never had such a suggestion from any UK manufacturer. Most will fall over themselves to be helpful.
 
Spoke to Whest yesterday. This is what they said when asked what the fault was, several components including some transistors were faulty, did i use a mains conditioner as these were deemed the culprits when they have previously seen similar faults , no i don't, when asked whether static could cause the damage they answered possibly and that static could damage the cartridge . Their opinion is that it has received a large voltage spike at some point. Unit is being returned to me unrepaired at my instruction and i have been charged a diagnosis fee which is fair enough, but have had to ask for the diagnosis report which they said they will email to me. Still waiting.
One other thing sprung to mind during the conversation, just recently we have had 2 short power cuts lasting merely a few seconds caused by the energy company and the phono stage and Naim were on both times , this could possibly be the cause . I sometimes listen at low volumes and only noticed the faults when winding the volume up a little more for some Led Zep, but it is audible at low volumes if you put your ear to the speaker. Once i receive the diagnosis report i will pursue the repair avenues' you have all kindly informed me of.
 
Don't know about your kit but my amps will run through a power off for about 10 seconds. The pre cuts out first.

Any surge should blow a fuse.
 
Sounds like OP has been BS'ed by Whest there... It won't be static for a start and then most of the time it's many many times more difficult to diagnose a fault that to fix it.... no way would you diagnose a fault precisely and then not go ahead and repair it.
 
russel said:
If anyone is feeling brave then epoxy potted modules can be unpotted with dichloromethane.
Click to expand...

Apart from price, I am unsure where the bravery comes in. That apart, you are as likely to get the thing apart with MEK as MC, at a fraction the price. Either way - a lot of faff, and MEK is flammable, unlike MC.
 
Well with service standards like this, it doesn't make one want to rush out and buy Whest.

I hope the OP can find someone who is more interested in helping with the repair.
 
i am inclined to agree with Arkless . Always had that feeling i was going to be stitched up . And still waiting for a report !
Will chase tomorrow.
 
Arkless Electronics said:
Sounds like OP has been BS'ed by Whest there... It won't be static for a start and then most of the time it's many many times more difficult to diagnose a fault that to fix it.... no way would you diagnose a fault precisely and then not go ahead and repair it.
Click to expand...
Well, I have dealt with things where the fault was obvious: a charred hole where some component with an unidentifiable number of pins used to be. Repairing that meant swapping out the PCB for a new/refurbished one. That's not the norm though.
 
mansr said:
Well, I have dealt with things where the fault was obvious: a charred hole where some component with an unidentifiable number of pins used to be. Repairing that meant swapping out the PCB for a new/refurbished one. That's not the norm though.
Click to expand...

Yeah ... right... That's obviously the type of scenario I'm talking about....:rolleyes:

I get sick of telling people who ask me to "find the fault and then give me an estimate to fix it" that I absolutely will never do that as most of the time the replacement component/s cost pennies and take minutes to fit... it's the decades of experience and 2 hours+ of my time in finding the fault and why it occurred (when there is a definite reason) that you're paying for!
 
Vinny said:
Apart from price, I am unsure where the bravery comes in. That apart, you are as likely to get the thing apart with MEK as MC, at a fraction the price. Either way - a lot of faff, and MEK is flammable, unlike MC.
Click to expand...

MC is a health hazard.
 
You must log in or register to reply here.


advertisement


Back
Top