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Old 18th December 2007, 11:41 AM   #41
d3imlay is offline d3imlay  United States
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The board is a 322. I found the problem. Open base-emitter junction on the 114 xistor. I put in an MPS A06 and it works. I'd like to know the xref for the xistors.

The setup procedure calls out test points that are not on this board. Can I get some help on that? Is the power supply schematic available?

Now for the problem that really concerns me. The knob for the balance slider is missing. Any ideas where I can find one?

Many thanks for the all of the help.
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Old 18th December 2007, 04:19 PM   #42
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Quote:
Originally posted by d3imlay
The board is a 322. I found the problem. Open base-emitter junction on the 114 xistor. I put in an MPS A06 and it works. I'd like to know the xref for the xistors.

The setup procedure calls out test points that are not on this board. Can I get some help on that? Is the power supply schematic available?

Now for the problem that really concerns me. The knob for the balance slider is missing. Any ideas where I can find one?

Many thanks for the all of the help.
It's always a great feeling solving the problem. The original replacement was a 2N4401, but the MPSA06 will work fine. It's just the cascode for the Jfets. I have a cross reference somewhere. I'll post it if I can find it.

As for the setup procedure, the one I posted is for the board you have, so I'm unsure what to make of this. Actually there are no actual testpoints, just resistor leads to clip onto.

I'm sure I have a knob somewhere, as long as you are not looking for one in perfect condition. I can drop it in the mail. Send me an e-mail with your mailing address.

Regards, Mike.
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Old 12th March 2009, 07:06 PM   #43
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Default GAS Thaedra schematic with parts ID

I have read the responces Mike made on this thread. I am also in need of the schematic with the parts listed. The unit I am working on allows the amp to output audio with the volume turned completely down.

The relay that the schematic and the posts state are missing from the board It is jumpered with two resisters parralelled together of unknown resistance beside where the relay should be.

I might have been in the field for 30+ but that just does not look right to me. There is no relay and that might be the reason it is allowing the amp to feede audio to through the pre-amp.

Ralph
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Old 13th March 2009, 12:42 AM   #44
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Default GAS Thaedra Jpeg

I have a Jpeg that I tried to attach, but it says the file is too large. so if anyone needs it to clarify what I am asking, I can e-mail it to you upon request.

Ralph
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Old 13th March 2009, 10:52 AM   #45
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There are two sets of output jacks. Check to see if someone modified the unit to output to a set of jacks straight off the line amp. The relays purpose is to mute the unit upon turn off and to delay its coming on line until it has become stable. The relay has no bearing on you getting uncontrolled audio with the control turned down all the way.
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Old 13th March 2009, 01:37 PM   #46
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Default GAS Thaedra

Burnedfingers,

I will double check the output lines so verify. I will then try to start from th beginning on diagnosing the other problem. My schematic does not list the parts values. Thank you for your reply.

Ralph
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Old 3rd August 2013, 03:22 PM   #47
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been trying to read the thread but information inside seem to conflict

The schematic posted as about the line stage i think belongs to thoebe rather than thaedra tuning procedure probably also .

I will include a picture of a board that i have which has 3 different pots per line ch. to adjust and i really cannot understand the principal of operation without a schematic .

while offset though is barely measurable still from times to times relay clicks without obvious reasons .

In between and in my search on the internet for more info with very bad results i found Andy Hefley that claims to be the true Master mind behind GAS and Audio alchemy while he also thinks that Jim Bongiorno was more in the bla bla side rather the design team .

the weird thing is that when i asked him for some information he said to me that doesn't hold any documentation from that era any more including GAS and Audio Alchemy .

In my world if a costumer ask me about repair procedures about one amplifier that i repaired 10 years ago i will remember any detail within a few seconds ...That is pretty quick considering that i repair an average of 400 amplifiers per year . In this case i find very weird that an audio person forgot how his own child was made ...

weird don't you think ?

pic of the board
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File Type: jpg DSC01340.JPG (124.1 KB, 78 views)
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Old 3rd August 2013, 04:02 PM   #48
llwhtt is offline llwhtt  United States
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The Thoebe and Thaedra I (one) had the same line stage. The picture you posted is the line stage from Thaedra II (two). The alignments on that board are a pain in the ***. Try emailing Mike at GASAUDIO, he is the only one left willing to talk about these classic pieces. Or possibly he will chime in here.

I have two Ampzilla IIa, a Son of Ampzilla, a Grandson of Ampzilla, a Thaedra II, and a Thalia, all I need is a Thoebe.

Craig
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Old 5th August 2013, 12:23 PM   #49
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Thanks for the info so far ...dropped a mail to mike will also give him a call later on tonight .

Kind regards
Sakis
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Old 5th August 2013, 02:55 PM   #50
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Got hold of mike over the phone just a few minutes ago ...

we talked to each other like colleges used to know one the other for 30 years , got all the information needed with in a few minutes

Thanks Mike doing things with you was an absolute joy !!
Kind regards
Sakis
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