This is the 110 'one hundred' 2100 RD. I hope someone here can explain how the channel switching with the foot pedal is suppose to work.
It seems that the pedal is the only way to activate the distortion channel.
There are 2 volume pots and 2 gain pots. Two of the Vol/Gain controls have written above the knobs on the faceplate that they are controlled by the foot switch. When the Foot Sw is pressed for distortion the LED lights and these 2, volume and gain, are activated and seem to work. When it is turned off the other volume pots is activated but the other gain pots is not. Instead the gain pot from the other channel works with the second volume pot. How is this possible?
Nothing seems to activate the first channel gain pot. Once in while that pot will come on but then drop out.
But it's hard to get it to do this at will.
The switch is working in the pedal. The gain pot that's not working is measuring ~100K and sweeps down to a few ohms.
The schematic I attached is closest to this amp but there are two 16 pin ICs, 14053 and 14016. These are not in the schematic. Am I using the wrong schematic? Is there a more accurate schematic out there?
Also, Does anyone have any experience with this type of problem?
edit:The schematic is correct, i finally located the 4053 and 4069.
The question is, are they working?
Check the electronic switch chips...
The RD-65 and RD100 amps used this schematic:
Pages 1 thru 3 show different versions of the internal circuits. In order, they are for the GD-1, GD-2 and GD-2A circuit variations. The GD-1 used a relay for the distortion switching (not a "Channel" switch, just a distortion circuit with separate pots switched in and added to the amp's single channel) and had 6CA7 output tubes. The GD-2 circuit replaced the relay with an all electronic switching system using the 4016 and 4053 switch chips. The GD-2A is the same as the GD-2 except the circuit was changed to accomodate the switch to the 6L6GC output tubes that occurred in the 1980 model year.
If your amp has the Black badges (Black background with brushed silver metal text) then you should have a GD-2A version and this is the schematic you should use. IC8 (4053B) controls the selection of the Gain controls and IC9 (4016B) controls the selection of the Volume controls. If the Gain controls are not switching properly check to see if IC8 is working correctly. This is probably where your problem is.
If you don't know how to check the switching you could simply change the IC. If the original IC was soldered into the PC board then a good quality (rolled pin military grade) socket should be soldered in its place so you can add or check a chip anytime you need to.
Steve