Silvertone 1484 Tremolo Help

[Helmholtz]

Looks as if you have to disassemble the roach and eventually replace it or at least either LDR or neon. Maybe someone can recommend a source. I assume a Fender roach would work.

Note; New schematic has V6 pin 6 and 8 cross labelled.

Oh well, these schematics really seem to be very unreliable.

[misterc57]

Looks as if you have to disassemble the roach and eventually replace it or at least either LDR or neon. Maybe someone can recommend a source. I assume a Fender roach would work.

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Opened the roach today. The LDR side was brittle and basically disintegrated as I unwrapped the package. Going to order a "Vibrato Optocoupler / LDR for FenderŪ Amps" on reverb.com

[misterc57]

I have not ordered the roach yet. I tested the bulb and it is working. It fluctuates with both the intensity and speed tremolo pots at what I believe to be expected operation. The light in the clear bulb flashes a light red color.

I am wondering if I can just order a replacement LDR? I am not sure what to look for in a replacement LDR. There is a lot available if you google "light dependent resistor" and they are under $1 each.

I have attached some pictures of the old LDR, the roach wrapper, and the bulb (bulb is still in circuit).

The old LDR has an id on the glass which I think reads CL-603. I was unable to find any info on this item number.

Thank you!

[52 Bill]

CL-603 is probably the Clairex part number. They made cds cells for many years back in the '60s.

You can just replace the photocell, but there are some things that you need to watch out for. The resistance range of the cell is important for the effect to be deep enough. The reaction time or how quickly the cell can change resistance will also be a big factor in how well the circuit works. I would suggest that you just purchase the Fender type replacement as the cell has been chosen for the correct characteristics and the new neon lamp will also be an added benefit.

[g1]

Agree with 52 Bill about the Fender opto, easily obtainable.
Should you want to go with the original LDR, datasheet is attached. And these guys show stock: https://www.questcomp.com/part/4/cl603/141273607

[misterc57]

The new Fender roach is clipped in and I have tremolo !.!.!.! However the rate needs to be slowed down. Is that possible by changing some values of the tremolo CRs? Suggestions?

Thank you!

[52 Bill]

Check the values of the three caps in the oscillator circuit C20, C21 and C22, and the resistors R49, R50 and R52 in the LFO.

If the caps have lowered in value, the speed will increase, so replacing them with the correct original values may be what you need. If the values are correct and the speed is still too fast, you may need to increase the values to get to a slower speed. There will be a point at which the values can be too high and the LFO will stall at slower speeds.

[misterc57]

The two .01 were below value. All fixed. I think I am done! My gratitude to everyone who helped, especially Helmholtz for being there at every step!

[Walker5]

Just wanted to thank all who posted on this forum- I've been working on a 1484 the past couple of weeks and ran into issues with tremolo- this forum really helped me hone in on the particular area of the issue and turns out I put the problem in myself - but this forum helped me isolate down to the issue and solve it! Tremolo working! Now an amp I found on the street back in the eighties that never worked is now working and sounds pretty good ! Thanks again! Plus it was alot of fun to repair it.

[Chuck H]

Just wanted to thank all who posted on this forum- I've been working on a 1484 the past couple of weeks and ran into issues with tremolo- this forum really helped me hone in on the particular area of the issue and turns out I put the problem in myself - but this forum helped me isolate down to the issue and solve it! Tremolo working! Now an amp I found on the street back in the eighties that never worked is now working and sounds pretty good ! Thanks again! Plus it was alot of fun to repair it.

Welcome. And go find more amps Your post actually gave me an idea for what could be a fun thread. "The amp you got for free (or almost)" I'm sure there's a ton of good tales here on the subject.