My lovely old NAD 3225PE was developing a bit of trouble. Mainly, the pre/outs seemed like they'd torn -- you know - *waggle, waggle, I can't... waggle ...get no...waggle...satis...waggle...faction...*
So I opened him up to have a look-see what the trouble might be... Maybe I could take a soldering iron and fix things up a bit? Throw some contact spray into the switches for good measure.
HERE IS WHAT I FOUND: Although some mounting plastic on the socket barrels has degraded, over the years, there doesn't seem to be any real connection problems visible to mine eye... But the most important thing is: NO SOUND ON LEFT CHANNEL. No matter what I do, no amount of 'waggling' helps... it's as if there is either no connection, or somethings just (god forbid) blown in there.
I've taken it round to my local electronic repair specialist who wants £10 earthly English pounds just to have a look. Fair enough, I thought... until I asked him what my worst case scenario might be...
AT THE SHOP: He told me that there is no way he can give me a quote until I hand him the tenner for some exploratory work... "Okay," I said, "What if THAT needs replacing", said I, pointing to the main transistors. "I have no idea" he said. "I will have to ring around and find out" "Okay then - So have you fixed an amp like this before? What is the most expensive component you could replace?"
Basically, I'm not happy with this. I don't mind paying him twenty-five quid, if first, he can tell me, by experience, or by looking the components up in a catalogue (which he should have) what the worst cost-scenario will be. I'd expect someone like him to say -- "Oh yes, I fixed a similar amp last month and it came to $$$...." But no. I didn't like this attitude. I hope I'm not being unreasonable here.
A POTENTIAL TROUBLE SHOOTING IDEA: A friend of mine has suggested NAD put crappy volume pots in, instead of proper potentiometers...? (I knew this, I think?) and that it's likely this that has given up. He suggested buying a cheap dual potentiometer from Maplins, etc and soldering it in, just to test it. So if not, then it's something else...
QUESTION: How on earth would I go about choosing the right one?
I want to learn how to do my own repairs. I wonder if this is possible, without a deep-rooted electronics background? I'm sure I can master the basics of soldering and assembly, as I'm quite skilled with my hands. I figure a method of 'try this, try that' troubleshooting of major components, I should find out what's wrong. Right...???
In the meantime, I'm tracking a few vintage NADs on ebay...
Any suggestions would be helpful from you guys. Sorry for the long post -- just a little frustrated at the moment.
Thanks-in-advance,
Varney
PS: Anyone with any suggestions on which would be a nice 'warm' vintage NAD, with a touch more 'Ooomph!' and detail than the 3225, would be nice also. I'll post a seperate question on that, closer to the time.
A/V, if you have a meter, you can test a lot of bits yourself. If you do not, you might purchase one, if you are indeed interested in tinkering a bit. Beyond that, leave it to a shop, Laddie.
I have to suggest that modern solid state amplifiers are not what you use to suddenly learn audio repair. There's too much going on and parts are often specific to a certain model. Tracing problems is often the result of having seen similar problems and knowing where to look first, second and third. A shorted output transistor can be replaced but if you haven't solved a problem in the power supply or set bias correctly, the new transistor will fry as soon as you power up. Obvious problems such as burnt resistors or broken connections can be scanned by anyone and usually repaired without any great amount of knowledge. But modern capacitors typically don't display visable signs of problems and certainly a visual inspection of an IC will tell you nothing short of catastrophic failure.
I think you are being unfair to the repair tech who didn't know the worst case scenario or the price of the most expensive component that could fail. Having worked with repair shops it sounds as if he was giving you the best knowledge he could under the circumstances and asking him to be more specific before he had the unit on a bench is a bit unreasonable. You have the right to choose who repairs your amplifier but what you've posted doesn't sound out of line to me.
If you want to troubleshoot your amplifier, you can plug "diy audio erpair" into a search engine and get some hints. The first thing most sites will expect, after the preliminary visual inspection, is the ability to read a schematic and that you have one in front of you. Without a schematic and the knowledge and skill required to interpret what you see in front of you in two dimensions into the workable knowledge of signal tracing which is in three dimensions inside the amplifier. If you lack this ability and the necessary tools to do troubleshooting, let the tech give you the estimate. Finally, if you don't know where both of your hands should go when dealing with an open chassis amplifier, you shouldn't even take the cover of.
Thanks Jan. That's an answer: Well, did need to ask if I were being reasonable or not. It's my net lack of knowledge which disarms me in any argument with a good repair specialist, you see. But I dealt with it very politely at the time, so as not to burn any bridges. I'll get a second opinion and then compare them. I might even go back to him, in the end... We'll see.
Yes - I do know where to - and where not to put my hands in an open chassis. Both, in fact. I know about the virtues of 'being earthed'. Still, I've decided now to leave it to someone who knows what they are doing. I think that is the safest and wisest option.
"I think you are being unfair to the repair tech who didn't know the worst case scenario or the price of the most expensive component that could fail."
Whatever the case, it does not exactly inspire confidence.
About three years ago, I had a television set repaired. I was given a no-obligation, very rough estimate over the phone. Free transport and delivery and then a free quote for the work; with a little grey area + or - for the unseen. It gave me a ball/park idea of whether or not to proceed. The television has been going strong ever since.
That is the kind of service we British have come to expect. They could do that, because they knew the routine with these models.
So, in this instance, I don't have the same faith, because this guy may never have seen the inside of a NAD; perhaps spending more of his time cleaning up dirty guide rails and lenses in all-in-one music centres, for the price of second hand one.
I really don't want to sound unfair - to anyone, but blind money is dead money. I just tend not to allow such things in my life.
I've just recently heard now of an old, experienced specialist not too far away, who does not charge for estimates. I'll try him.
I paid my tenner. I've finally got the amp back, after having to pester him for 3 weeks.
I took it in and asked him to just reset the bias to stop it overheating. The tenner was for a quote and to reset the bias. The tenner was for him to open up the box and search for diagrams and schematics - oh and phone around for parts for a complete repair.
When finally he'd finished with it, he said he'd set the bias as best he could without the circuit diagram.
I said "Where is the circuit diagrams I paid for you to get for it? Use those"
"I don't have any. Plus I would need to put it through an oscilloscope"
"Okay" says I... "Put it through your oscillioscope then"
"I don't have one"
"Okay - how much is it going to cost to put it right then?"
"65 quid"
"Okay - lets get this right. You can't find a circuit diagram (even though I can find one on the internet), you don't have an oscilloscope and you want 65 quid.... What for?"
"To change all the transistors"
"One channel is down mate. Why ALL the transistors....? "
"Because that's what it needs"
"How do you know that's what it needs if you can't even find a schematic and you don't have an oscilloscope, I'm willing to bet you haven't even researched how much the parts are. Forget it. Keep your tenner... I'm off to find a proper repair tech. You obviously don't know where to start, any more than I would."
So... My hunch was right. He's used my enquiry as a licence to print money. In future, I will go with my instincts. Proper repair specialists have fixed amps before. That is how they will know what a ball park figure is likely to be. Last time one came in, they can use it as a reference. He's never even seen the inside of a NAD before I can tell. I smelled a rat and basically didn't act upon my instincts. My own fault.
The amplifier is still overheating. He probably hasn't even touched it. Rip off!
I also, the same day, had to return the universal TV remote he'd sold me earlier which didn't work at all.
THEN my friend tells me - he took the back off his girlfriend's watch to replace the battery, with a stanley knife and scratched the casing rather badly.
I'll find a proper NAD dealer and see if they can recommend anyone to look at it. Damn, I should have done that in the first place.
