Two Kenwood KR-5600s in the house, need help on one

U-C, Nichicon, Cornell, Panasonic, and all the usual brands should be safe. Generally, most of these larger distributors won't even stock "bargain" or off-brand parts, and risk their reputations.
 
The parts arrived today. I've read that they are smaller, but I wasn't expecting this small. I looked at the specs but don't comprehend too well in millimeters. The 25 volt capacitors are tiny with short little leads on them. The 35 volt are maybe half the size of the caps in the board and the leads are plenty long to work with. I bought plenty so unless there is a reason not to, I will use the larger profile caps. They are all 100 uF.
 
You didn't say which brand and series you ordered. For power supplies I usually get Nichicon UHE, UPW or UPM. I measure the diameter of the originals with a cheapie HF digital caliper and order replacements to match, which is usually 1 or 2 voltage ratings higher than the originals. Use the 35V.
 
you will see a lot of us post mouser or digikey part numbers for everyone to review.

if you have the capacitance correct, and voltage (or a bit more), lead spacing is ok, you should be good.
 
I finally got the company out of the house and found a couple of hours this afternoon to swap out the components that were thought to maybe be bad. The zenor and the two capacitors all tested good but were replaced with new. I don't know if the transistor was good or not, but I changed it out anyway. While I was working on the board I noticed that C14 seemed loose. It appeared to be soldered solidly, but it also had sort of a spot on one side that looked like it had been pretty warm. I pulled it out and it tested bad so I put a new one in. I put everything back together and turned it on. There was 13 volts going to the tuner so I hooked up a speaker and had some loud static. I had broken the tuner string early on so I restrung the tuner with some .023 Diamondback bowstring serving material. It may be just a hair thinner than the old white stuff; probably nylon or rayon that was used originally. The new string is Dyneema which is far superior to the materials available in the seventies. I think that it will work fine. If it doesn't, I have some heavy nylon serving string that I will try. I made a makeshift dipole antenna and hooked it up. Fired the thing back up and I have music! I haven't checked anything other than FM but will get around to that sometime this week. The only odd thing that I noticed it that I do not get a voltage reading on the two pins that are +39volt and -39volts. I was getting a reading until I hooked up the wires to what I think is the amplifier. That's pretty strange.
 
This receiver still has several problems. I hooked it to the same antenna that I have been using on my other KR-5600 and can only pull in one FM station strong enough to light the stereo light, and one other so weak that it won't even budge the signal meter. My other 5600 will pull in probably twenty FM stations with most of them having good to excellent signal strength. I also found that the right speaker channel is about 80% weaker than the left. Still lots of crackling when I switch things or use the tuner. I will get into it and do some more cleaning and lubing and take a look at the wiring going to the antenna posts. I hooked up a CD player and that section works fine other than the problems with crackling. I don't even own a turntable, so the phono input is still untested. Not wanting to get too far ahead of myself, but are there any components on the tuner boards that tend to get weak with time?
 
Thanks Steve. I will do that tomorrow. I couldn't sleep last night so I was running everything through my head making a mental list of things to do and it occurred to me that since both right sides are acting up, the problem just may be in the right speakers. That was the first thing that I checked this afternoon and sure enough, I had the wire stuck in a bit too far and the insulation was under the nut keeping it from making good contact with the speaker wire. I turned on the lesser of the two units and was amazed at the sound. I never have had a system that will crank out the music like this little receiver. I had a very pleasant afternoon cleaning up the nicer unit and listening to some old CDs that I picked up while I was in town today. I just fiddled around and cleaned every electrical connection, switch and pot on it. Lubricated it then buttoned it back up. I will test it out tomorrow to see if the cleaning eliminated the crackling.
 
I cleaned the tuner to no avail. Still just the one station coming in. I did some research and decided that an alignment was in order. I built a non conductive screwdriver and it took all of about five minutes to do the cheap and dirty alignment that I had read about. The tuner is now quite strong and seems better than the other receiver. I'm picking up the same stations with less static on this radio. My other one has static when the stereo light is lit and I have to bump the frequency up just a little to get rid of the static. The stereo light turns off, but the quality is better. Whoever had this radio had tightened the adjustment screws on the variable capacitor as tight as they would go, probably thinking that they were too loose.
 
Hello I know this over a year old but would you have a list of the parts you ordered especially the hot transistors on the board.

Thanks
 
If you don't have one already, google "AK Database" which has a service manual available for this receiver as well as others. All the transistor and semiconductor parts numbers are available there. Kenwood parts lists are one of the easier lists to navigate through.
This link should give you a PDF of the manual.
http://akdatabase.org/AKview/albums/userpics/10007/Kenwood KR-4600-5600 Service Manual.pdf
I have a couple of those lists and the schematics. The problem is that the parts list is forty to forty five years old and I'm not knowledgeable enough to chose a good audio capacitor from the choices available today. I also really dreaded measuring and comparing the old to the new. At least I was smart enough to bring home the bag of old caps. Those will be easy to measure out of the boards. Thanks for the link eiraved.
 
Nichicon audio grade should be as good as the Elnas that Kenwood put in there. I use UKL series low leakage caps where called for in the parts list, and Nichicon non-polar when those are specified.

Most small caps don't mount flush with the board, I'd only worry about it with the larger "surge" caps in the power supply portions of the circuit. And even those are going to be much smaller than what is in there.

I would guess that ANY modern electrolytic of general purpose or audio grade you put in would be as good or better than the original parts, and definitely better than the originals 45 years old.

Capacitor specifications have not changed any, just get the proper uF rating and equal or higher voltage rating. Don't change the uF rating except for filter caps were you may not find an exact match that fits (I was lucky with the KA-80's -- snap in which are easy to get).

Transistors and diodes you will need to find modern equivalents. Most of that information is here on Audiokarma if you use the search function though.
 
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