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Re: Kustom III PA [message #23127 is a reply to message #23122]

Wed, 17 June 2015 02:16

Autoharp
Messages: 14
Registered: April 2015
Location: Warren, MI

Junior Member

Problem solved! It works great!

I was totally frustrated. Injecting signal, signal tracing, nothing was happening...until...

I started measuring voltages on the 741 op amp on the graphic equalizer...pin 4, supposed to be -12 volts - measured -13.2, no big deal. Pin 7, supposed to be +12, measured -5.4 What the hey? Checked the power supply to the board - -13.5 instead of -12, close enough, but -5.4 instead of +12

Went back to the zener diodes in the power supply, + and - 13.5 - that's OK, I'm on to something!

Power goes to a Molex connector on the master / reverb board, then comes out from other terminals to the graphic EQ then daisy-chained to the preamps.

Correct voltage in, bad voltage out. Pulled the board out again for the umpteenth time and looked at the solder on that connector...there was my problem. Very little solder, taking the harness connector off to remove the board did it in.

Used some 26 gauge bare copper wire and made figure 8's around the 3 triplets and soldered it good, put it back together - presto! It's awesome!

Combination of idling and playing my instrument through it for two hours. Output transistors are toasty but not super hot like they were.

Band practice is Thursday, and they have a gig Saturday afternoon. I think it will work!

Thank you everyone for your help! I'll be doing photography for their gig, so I'll report back.

And cleaning the controls fixed that noise problem too!

Autoharp Bill
Beautiful Downtown
Warren, Michigan
USA

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[Message index]

		Kustom III PA By: Autoharp on Sun, 19 April 2015 00:02
		Re: Kustom III PA By: chicagobill on Sun, 19 April 2015 02:48
		Re: Kustom III PA By: stevem on Sun, 19 April 2015 06:55
		Re: Kustom III PA By: Autoharp on Tue, 21 April 2015 09:20
		Re: Kustom III PA By: Autoharp on Mon, 20 April 2015 12:10
		Re: Kustom III PA By: stevem on Mon, 20 April 2015 12:41
		Re: Kustom III PA By: Autoharp on Tue, 21 April 2015 09:10
		Re: Kustom III PA By: chicagobill on Tue, 21 April 2015 11:24
		Re: Kustom III PA By: stevem on Tue, 21 April 2015 13:05
		Re: Kustom III PA By: Autoharp on Tue, 21 April 2015 14:03
		Re: Kustom III PA By: chicagobill on Tue, 21 April 2015 14:11
		Re: Kustom III PA By: Autoharp on Tue, 21 April 2015 22:42
		Re: Kustom III PA By: Autoharp on Wed, 22 April 2015 09:37
		Re: Kustom III PA By: chicagobill on Wed, 22 April 2015 13:22
		Re: Kustom III PA By: Autoharp on Wed, 22 April 2015 16:11
		Re: Kustom III PA By: chicagobill on Wed, 22 April 2015 17:29
		Re: Kustom III PA By: Autoharp on Thu, 23 April 2015 15:05
		Re: Kustom III PA By: chicagobill on Thu, 23 April 2015 15:32
		Re: Kustom III PA By: Autoharp on Thu, 23 April 2015 22:27
		Re: Kustom III PA By: chicagobill on Fri, 24 April 2015 01:10
		Re: Kustom III PA By: stevem on Fri, 24 April 2015 06:18
		Re: Kustom III PA By: Autoharp on Fri, 24 April 2015 16:54
		Re: Kustom III PA By: stevem on Sat, 25 April 2015 06:54
		Re: Kustom III PA By: Autoharp on Sun, 14 June 2015 21:05
		Re: Kustom III PA By: Autoharp on Sun, 14 June 2015 23:54
		Re: Kustom III PA By: stevem on Mon, 15 June 2015 06:26
		Re: Kustom III PA By: Autoharp on Wed, 17 June 2015 02:16
		Re: Kustom III PA By: stevem on Wed, 17 June 2015 06:17

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