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Old 16th July 2007, 07:11 PM   #1
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Default Getting a vintage amp to work

I have recently acquired a vintage amp (Model TP45) made my Webster Electric. There are not a lot of things that I can find out about it except for what is on the back of it.

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i don't know what the line screw things mean and have not used them or that button which seams to be the ground. I have tried to use 1.5 amp slow blow fuses, but they keep getting blown. Any help on getting this thing running would be great. Thanks.
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Old 16th July 2007, 07:18 PM   #2
anatech is offline anatech  Canada
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Hi DeadSpeaker,
Okay, you have an old mono PA amp.

Fuses blowing instantly means you have a fault in a high power stage. Could be shorted rectifier diodes, main caps or output stage. There may be a combination of faults since a new fuse was put in. It's not unusual to see a blown output stage and shorted rectifier diodes. What may follow is an open transformer primary if you keep sticking fuses in it.

-Chris
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Old 16th July 2007, 07:24 PM   #3
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Thanks for the reply. That is a lot of information. So what should I do in order to get it running?
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Old 16th July 2007, 07:50 PM   #4
anatech is offline anatech  Canada
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Hi DeadSpeaker,
That really depends on how much you know and what equipment you have. An experienced tech may be able to repair it properly and set it up without a diagram. A layperson may need to take an electronics course and but test equipment and a manual to get it working.

Where you you fall in that range?

-Chris
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Old 16th July 2007, 08:09 PM   #5
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Well It is not rocket science to read the values off of capacitors and solder new ones on, but I'm not sure if it is worth it. I'm trying to use it to power a speaker cabinet that has a input value of 65 watts. I know this amp is not enough to meet that requirement, but I wanted to see if it would at least drive the speakers some what. So should I give up my dreams and ditch this thing or what? Thanks for the help.
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Old 16th July 2007, 08:21 PM   #6
anatech is offline anatech  Canada
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Hi DeadSpeaker,
Quote:
I'm trying to use it to power a speaker cabinet that has a input value of 65 watts. I know this amp is not enough to meet that requirement, but I wanted to see if it would at least drive the speakers some what.
It may have enough power to burn those speakers out. Maybe not. It will be loud considering that if you double your power, it's only a 3 dB increase. That's not much.

Quote:
Well It is not rocket science to read the values off of capacitors and solder new ones on
There is much more to it than you may think. How stupid do you think these good techs are. This may be your first error and I think you may have just insulted all the good techs out there! I don't know where you got the idea that properly repairing an amplifier is easy. BTW, most techs can not repair an amp properly.

But I did ask, what equipment do you have. That included meter(s), soldering stations (notice it isn't an iron) and anything else. Also, what experience do you have? Is there someone who can help you?

Quote:
So should I give up my dreams and ditch this thing or what?
I don't know. Are you willing to put any effort into this or not?

-Chris
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Old 16th July 2007, 08:59 PM   #7
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Quote:
Originally posted by anatech



I don't know. Are you willing to put any effort into this or not?

-Chris

a mite overbearing -

DeadSpeaker did not ask to become a tech.

find out, if hes got a meter, and walk him through


71





http://www.angelfire.com/vt/audio/tp45.html
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Old 16th July 2007, 09:01 PM   #8
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I don't have any experiance with this sort of thing at all. The only equipment I have is an ohms meter (Which for whatever reason only responded to about 50% of the resisters and other thingums) and the screw driver that I used to open the thing up. I'm willing to spend a few dollars on this (like $30 US) but I don't want to get far into this if there is not any hope that it will perform. My main goal anyway is to drive those speakers at a level that is adequate for a small venue (used for singing in a rock band at a club)
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Old 16th July 2007, 09:18 PM   #9
anatech is offline anatech  Canada
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Hi tomtt,
Great link. Thanks.
Quote:
a mite overbearing -
True, as you know, tone is everything. But you do know I'm more than willing to help as long as the other party is willing to work and learn something.

Thank you.

-Chris

Edit: from Tom's linked site, the schematic .....
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File Type: gif webcor_tp45schematic (large).gif (43.9 KB, 488 views)
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Old 16th July 2007, 09:27 PM   #10
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Quote:
Originally posted by DeadSpeaker


The only equipment I have is an ohms meter

what brand and model number do you have?
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