Can anybody help me out with the tremelo circuit on a silvertone 1484? It sort of works, almost non noticable effect. I have tried the following: new tubes, new 100k pot, new 1 meg pot, replaced every cap in the trem circuit. The multi stage filter cap has been replaced with individual caps. All of the resistors meter out correctly.
Everything else functions fine, including the lousy reverb!
Silvertone Treml-no
Moderators: pompeiisneaks, Colossal
Re: Silvertone Treml-no
IF you look at the schematic, you have one of those opto-isolator circuit.
http://www.el34world.com/charts/Schemat ... ne1484.pdf
You can replace that with something similar to this (which is a bias vary tremolo):
http://www.el34world.com/Forum/index.php?topic=604.0
With respect, 10thtx
http://www.el34world.com/charts/Schemat ... ne1484.pdf
You can replace that with something similar to this (which is a bias vary tremolo):
http://www.el34world.com/Forum/index.php?topic=604.0
With respect, 10thtx
Re: Silvertone Treml-no
Thank you for the quick response! That amp is not mine, and I can not alter it. However, making it perform at it's best would be great. I have read every article and schematic I can find. Safe to say that I am stumped!
What would you say is the most likely reason it doesn't work?
I'd love to repair it, and then never see it again!
What would you say is the most likely reason it doesn't work?
I'd love to repair it, and then never see it again!
-
Kagliostro
- Posts: 549
- Joined: Wed Dec 30, 2009 12:09 am
- Location: Italy
Re: Silvertone Treml-no
Have you try an other tube ?
Kagliostro
Kagliostro
Re: Silvertone Treml-no
Yup. I've tried a new tube.
Can anyone give me data on the photo cell, light bulb thing? Can you swap it out for the Fender version? Do they actually die?
If I shine a flashlight into the photo cell, it kills the output of the amp. So I assume it is working. However, the neon bulb will not light except when metering for dc across the trem tube. Also lights if you put meter on the bulb lead. So, the bulb works, but it's not getting the power in the correct manner. And, when you touch a meter lead to pin 1, the amps makes a high pitched oscillation.
Pretty sure it is the fact the little lite doesn't turn on and off.
Any ideas?
Can anyone give me data on the photo cell, light bulb thing? Can you swap it out for the Fender version? Do they actually die?
If I shine a flashlight into the photo cell, it kills the output of the amp. So I assume it is working. However, the neon bulb will not light except when metering for dc across the trem tube. Also lights if you put meter on the bulb lead. So, the bulb works, but it's not getting the power in the correct manner. And, when you touch a meter lead to pin 1, the amps makes a high pitched oscillation.
Pretty sure it is the fact the little lite doesn't turn on and off.
Any ideas?
Re: Silvertone Treml-no
I think you might have an opto-isoloator that uses an incandescent bulb. If you do, the Fender part won't work, as it has a neon bulb.
The part is obsolete and I've looked high and low for one for my Gibson. AFAIK, they simply can't be found. It is easy enough to build one, but the problem here is finding the right bulb. The good news is you have a working LDR. For starters it is difficult to know what is the correct bulb. CMI makes a variety of bulbs and you might find a suitable one. As I recall, the application calls for a bulb that has a rather low mA rating, but I'm not sure. Anyhow, if you are careful, you can retain the LDR as you proved it works, make a small tube of plastic or cardboard, insert the bulb with some sort of putty or epoxy to keep it in place, cover it all with black heatshrink, and that's all there is to building one of these. If you are really lucky, you might be able to change the bulb on the existing opto, but these things tend to be rather delicate.
The part is obsolete and I've looked high and low for one for my Gibson. AFAIK, they simply can't be found. It is easy enough to build one, but the problem here is finding the right bulb. The good news is you have a working LDR. For starters it is difficult to know what is the correct bulb. CMI makes a variety of bulbs and you might find a suitable one. As I recall, the application calls for a bulb that has a rather low mA rating, but I'm not sure. Anyhow, if you are careful, you can retain the LDR as you proved it works, make a small tube of plastic or cardboard, insert the bulb with some sort of putty or epoxy to keep it in place, cover it all with black heatshrink, and that's all there is to building one of these. If you are really lucky, you might be able to change the bulb on the existing opto, but these things tend to be rather delicate.
Re: Silvertone Treml-no
OR you can simply rewire it to NOT need the opto-isolator and use bias vary tremolo like the Fender.
With respect, 10thtx
With respect, 10thtx