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PostPosted: 25 Apr 2012, 17:38 
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Joined: 25 Apr 2012, 17:18
Posts: 3
Location: Florida
I'm fairly new at this and there don't seem to be may professionals to bring units to for testing when I run out of ideas or don't have the time to do something myself. Recently had an experience with a store front outfit I took a newly purchased Scott 222c to check on the power supply because it wasn't coming up. They got back to me and said the transformer was shorted and the switch broken (not something I was expecting). They proposed to change it out for a new transformer with a solid state rectifier. I declined and said I would just put the unit in storage and look for a spec transformer. When I got the unit home I opened it to find they had detached (de-soldered) and/or cut ALL the main transformer leads/ and no labels. I protested and they claimed they did HAD TO DO IT for 'liability' reasons. Would like to get anyone's take on this situation.


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PostPosted: 27 Apr 2012, 22:47 
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Joined: 04 Jun 2008, 20:59
Posts: 4192
Location: Arizona, USA
Hi, I suspect the reason was for testing purposes and the liability issue is a smoke screen. I find it a bit unlikely that both the switch and transformer were bad. Either could cause it to not power up, but I suspect at most the switch might not be in great shape and ought to be replaced, but was still functional. Most transformers are replaceable. The challenge is to locate one that will both fit in the original space and provide the same voltages and currents. You might consider contacting Hammond and see if they have one. Also you can put the word out on the various forums and see if anyone has done this before (very likely).

BTW, as a business owner I can nearly envision why someone might do what they did, but on a piece of vintage gear it is really unacceptable. It was already failed, no need to cut the wires. There is the possibility that one of the custom transformer companies can rewind or repair the original transformer. Check the web for such services.

Good listening
Bruce

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PostPosted: 02 May 2012, 14:56 
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Joined: 25 Apr 2012, 17:18
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Location: Florida
What do you think the smokescreen was meant to cover?


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PostPosted: 02 May 2012, 19:39 
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Joined: 04 Jun 2008, 20:59
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Location: Arizona, USA
Hi, Just a guess here and I could be wrong... They probably had a source for a replacement and were getting ready to use it. Then either decided not to for some reason or if they gave you an estimate on cost that was high and you didn't want to spend that much. Also the replacement if such was the case would not look like the original and you had indicated you want to keep it original. These are possibilities and I may be casting dispersion where none is deserved. Still anytime I have seen a shop diagnose a problem of this sort of nature, and not get the job to fix it, they usually return the item in the condition it came in.

Good listening
Bruce

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PostPosted: 02 May 2012, 20:50 
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Joined: 06 Apr 2009, 10:08
Posts: 1667
Location: US Pacific Northwest
The rapid pace of electronics technology development has really created problems for electronics repair, especially here in the US.

Much of the electronics sold today are integrated products that can only be repaired with OEM parts from the original manufacturer. Unfortunately, most small business can't get access to most of these parts so that has forced them into a situation where they can either do simple repairs (such as replacing a switch or power cord, swapping power supply capacitors, or changing connectors) or just recommending a replacement. The unfortunate side effect has been a general erosion of the troubleshooting ability by the staff in such business and (even more unfortunately) the rise of some less than reputable shops. When I worked in a TV repair shop over 30 years ago we serviced all types of electronics and had a large stash of decent test equipment. We were taught troubleshooting techniques by the owner who actually had an Electrical Engineering degree and decades of experience. We never altered a piece of equipment without the customer's consent and surely never returned a piece of equipment to a person in worse shape then it arrived in our shop. Today much has changed and shops like the one where I worked are virtually nonexistent.

Now, when taking something like a piece of tube equipment in for troubleshooting or repair, it's imperative that you do some investigation, ask some questions, and make some things clear before leaving anything with them. Here is a list of things I would recommend.

1. Open the unit and inspect it before taking it in for repair. Take some pictures and make sure that you have a good understanding of the condition of the equipment and a way to prove it.
2. Make some inquiries of the business owner or manager; things such as what educational certificates do their technicians hold, are they qualified to work with high voltage electronics, and what experience do they have with such equipment. Don't be shy about asking for references and to see some things they've repaired.
3. Make it very clear what you expect them to do and get it in writing. If it's just troubleshooting, make sure you make it clear that the equipment is to be returned in the EXACT same condition as when you brought it in. If you want a repair, make sure they call you with the diagnosis BEFORE any repairs are made. Make them tell you exactly what the intend to do to the unit. Most importantly VERIFY what they have done BEFORE you leave the store. They should be willing to show you exactly what repairs were made and explain why.

I know that some of these steps may sound extreme, but this really is a case of "let the buyer beware". Tube equipment is not common enough in most places to not take these types precautions.

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PostPosted: 03 May 2012, 08:30 
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Joined: 25 Apr 2012, 17:18
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Location: Florida
Mat, you make really good points. To some extent I asked all those questions, the place was recommended (by someone I didn't know but claimed to be a guitar repair person and also by a Sam Ash store maintenance dept). And I even insisted on speaking to the lead tech/owner and did explain that no matter what else I wanted all the diodes/capacitors/resistors in the power transformer chain checked out for values. There was no disagreement on that either. Based on what I saw (there were lots of certifications on the walls) and what was said between myself and the tech before leaving nothing gave rise to any expectation of what finally happened. The way the unit was returned was truly a surprise. I can only think that his motive was NOT 'that detaching all transformer leads was a matter or issue of his 'liability", the only explanation I was given on both occasions I spoke with the shop afterwards. Worse still, he refused to re-attach the leads or even label them.


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