Trouble with iron upgrade installation

[Doc B.]

Disconnect the red and blue wire from the circuit, in the amp that doesn't work. Connect your red test lead to the red wire and the black test lead to the blue wire. Set your ohmmeter to about 20K ohms and tell us the reading. You must have good contact between the test leads and the red and blue wires.

[Pfenning]

Doc, I did just like you asked and the reading was 2.3?? mega ohms. My meter is autoranging. I assume this means the OT is fine and I have another issue.

[braubeat]

If it was me, I would completely disconnect the transformer from the circuit and test it for resistance. Hook the test leads to bare wire.
That way you know fore sure you are not looking at bad solder joints.

Michael

[Pfenning]

Yes, I disconnected the red and blue wires. I did not disconnect the black and orange speaker tap wires. Will that make a difference?

[Grainger49]

It shouldn't make a difference if you are measuring DC ohms, no normal inexpensive hand held meter measures AC impedance.

[Doc B.]

Doc, I did just like you asked and the reading was 2.3?? mega ohms. My meter is autoranging. I assume this means the OT is fine and I have another issue.

2.3 megohms is essentially open. Not good. Should be in the hundreds of ohms. Since you have disconnected from the circuit you know the open is not at the terminal strip where the red and blue leads connect. So the open must be at the end of the leads where they connect to the coil inside the transformer, or in the coil itself. Perhaps a lead was pulled on and that damaged the connection? Has this transformer ever been used before?

[Pfenning]

No, I bought the iron upgrade kit from you 2-15-06 (I still have the receipt). I just got around to installing c4s and iron upgrade kit recently. I was building a house at the time I purchased it, and didn't even have my system set up. Once the house the house was built, I bought a business, and 6 years slipped by. I have been enjoying them in stock form, but decided it was time to hot rod them. I don't think I was rough during installation, but I suppose I could have damaged it. What are my options?   

[Doc B.]

If you are willing to send it to us I'd be happy to take a look at the transformer to see what can be done, and discuss it with Mike if necessary.

[Pfenning]

OK, I'll send it out today or tomorrow.

[Doc B.]

Ahh, apparently I misunderstood. I thought that you had MagneQuest upgrade transformers. PJ informs me that these are Edcors. That was quite a while ago. I do recall ordering one batch of Edcors in which the blue lead was loose on almost every one. We tried to get help from them to correct the problem and we were informed that they had never made a transformer that had a loose fly lead, so we must have broken the entire batch ourselves. We stopped using Edcor after that. I'll see what I can do to repair it.

[Doc B.]

Just a quick follow up - received the transformer this morning and some minor surgery with an Exacto knife allowed me to see inside and confirm that the end of the primary was indeed disconnected from the blue flying lead as we found with several of these transformers from a particular production run. I'll solder it back on, secure the connection better and button it back up.

[Pfenning]

Excellent news! Let me know when it ships back out. I just returned from vacation with a stack of albums from Amoeba Music in Hollywood (the largest selection of new and used vinyl I've ever seen). I can't wait to get the amp up and running and spin some vinyl. Thanks Doc.

Pfenning

[Grainger49]

These guys are so good it makes my head swim.