Hiya,

I have 2 SCR-8's I got off of Ebay this past week. One works but is kind of beat, and smells like smoke. The second one doesn't work, but is flawless. And I mean flawless.

What happens is upon turning on, the power LED lights, then quickly fades and nothing works. If I leave it off for a while and power up again, the radio will play softly, but distort with any kind of volume before going dead. So this seems like a power supply issue. (It doesn't work on batteries at all).

Since I have a working unit I can replace parts until I find the broken piece, but is there a logical place to start? I plan on plugging both in and tracing the input voltage paths with a multimeter to see where they differ. Maybe the transformer or caps are bad. Any other suggestions?

regards, Randy

I think member "bashngu" could probably help you out...he seems to really know his stuff

-gsbadbmr

It is pretty simple to swap the guts from one to another

There is a 1/8 th watt resistor in the feeds of both power regulators which seems to be another trend failure on this and the GE blockbuster. If memory serves its a 2.2 ohm resistor which at that resistance seems to act as nothing more than an inline fuse. I have had to replace them on several of these and have upgraded to 1/4 watt resistors. What you are explaining is happening sounds very similar to the effects I have seen when these resistors crap out. One of the regulators power the tuner and the amp chip, the other regulator powers the cassette mechanism. I have had both go out. I had one of them crap out as I was playing it and what I had left was low volume with distortion, the power light went out and only the green tuning light would come on but very faintly. Hope that helps.

I swapped the power supplies outright and that did not work. So I had to switch out the main board with the tuner/amp/switches and all. Also successfully repaired the broken power switch. Always amazed at the multitude of different mechanical switch designs.

I would rather have not switched the whole board because the donor box has a rancid smoke stench that is gut-wrenching to me, but I do now have a perfect looking and sounding radio. Now I need to fix #2. I could use it as the garage radio without risking the pristine one.

Thanks for the details on the resistor bashngu. Both power supplies put out similar voltages to both the tuner and the cassette, and switching them out did not help so the regulators *appear* fine. But I will check that out.

Also, wouldn't it be neat to devise a way to use the cassette controls to control an ipod that is hidden inside the case? Merge 21st century tech to 80's coolness!

The resistors I am talking about are NOT in the power supply. The resistors are next to the power regulators on the main board. Look for the resistor which is right before the center post on the regulators. The center post is the power feed to the regulator. If I remember right you should be getting around 15v or 18v at the center post of each regulator. Either way I was getting around 7-9V. If one is less its because the resistor im talking about took a SH!T and the resistance is now astronomically high compared to the original 2.2ohms. The resistor is what is in circuit prior. Im pretty sure you will find the ohms reading to be much much higher than 2.2 ohm. If thats the case then there is your problem. If not then kick it real hard, maybe it will help.

quote:

Originally posted by peltzr:
...I would rather have not switched the whole board because the donor box has a rancid smoke stench...

This may be a pain since you got it back together but you can take the main board and give it a gentle cleaning with isopropyl alcohol and a soft toothbrush. Slow and gentle with an ample, but not too generous amount of alcohol. Be sure to lube all switches and controls with De-Oxit after it has time to dry. Bye-Bye Smoke smell!