Received a 100 w Randall head (RH) and the outputs were shorted and some other smaller support components were toasted as well. Replaced what I could find gone and fired it up again. Played it for a couple of hours and it was great. Installed the chassis back in the cabinet and within minutes, the damm thing smoked again..this time taking out evrything I had replaced to begin with plus a few extras as well.. Re-ordered all the parts again and re-installed everything. Hooked up a series light blub this time to prevent another BBQ..the amp works now but very badly distorted. Problem is I can't find a schematic for the pre-amp board to see if I have the correct signals coming from the pre-amp. The output schematic shows a connector from the pre-amp with three pins...one for ground and I guess the other two are for the signal. Pin 3 of this connector has a signal but pin 2 does not. Disconnected the connector and ran a signal from a generator into pin 3....a somewhat low signal but never the less it was present...then ran the same signal into pin 2 and there was a much louder signal coming from the speaker cabinet. However, when checking the harness which comes from the pre-amp board, there is no signal on this wire...Does anybody have a schematic for the pre-amp board for this model of Randall? Maybe when everything blew up it might have also taken out something on the pre-amp board as well and a schematic of the pre-amp section would be a great asset in solving the problem. Thanks to anybody who can help me out with this one....
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Originally posted by bsco View PostReceived a 100 w Randall head (RH) and the outputs were shorted and some other smaller support components were toasted as well. Replaced what I could find gone and fired it up again. Played it for a couple of hours and it was great. Installed the chassis back in the cabinet and within minutes, the damm thing smoked again..this time taking out evrything I had replaced to begin with plus a few extras as well.. Re-ordered all the parts again and re-installed everything. Hooked up a series light blub this time to prevent another BBQ..the amp works now but very badly distorted. Problem is I can't find a schematic for the pre-amp board to see if I have the correct signals coming from the pre-amp. The output schematic shows a connector from the pre-amp with three pins...one for ground and I guess the other two are for the signal. Pin 3 of this connector has a signal but pin 2 does not. Disconnected the connector and ran a signal from a generator into pin 3....a somewhat low signal but never the less it was present...then ran the same signal into pin 2 and there was a much louder signal coming from the speaker cabinet. However, when checking the harness which comes from the pre-amp board, there is no signal on this wire...Does anybody have a schematic for the pre-amp board for this model of Randall? Maybe when everything blew up it might have also taken out something on the pre-amp board as well and a schematic of the pre-amp section would be a great asset in solving the problem. Thanks to anybody who can help me out with this one....
but I hope it can help you.
Good luck,Last edited by doctor; 03-02-2012, 04:27 PM.
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