Two Problems with Rhodes Mark II Suitcase

[kiddakota]

First, when I engage the vibrato, which, of course is tremolo, one of the sides (l,r) doesn't work. When the red indicator light is blinking, the sound is off when the light is on, and the sound is on when the light is off. The intensity and the speed work fine. When I swap the speakers in the power amp section, the side not working switches so the problem must be upstream in the preamp.

Second, Power Amp Input Channel A is quieter than Power Amp Input Channel B. I verified this by plugging a bass into each channel and comparing the volume coming out of the suitcase. The problem is also present in the headphones where one side is quieter than the other. The quieter side is not drastically quieter but it is noticeable.

[kiddakota]

I replaced the four caps on the power amplifier as well as RC4558p at U2 on the preamplifier assembly. Neither of those solved the problem. Any thoughts? Anyone?

[Jenzz]

Hi :-)

I would highly recommend first to pull out the 2 power amp boards and the preamp voltage regulator board and resolder all Molex PCB connector pins.

Because of their thickness, there was often not enough heat distribution during the wave-soldering process, causing cold solder joints here.

...looks something like this:

https://vinatronic.com/blog/cold-solder-guide/


Jenzz