Proud new Astrosonic owner has questions

Hello all,

I recently came across a 1967 Astrosonic at a Goodwill and took the plunge! I've always wanted one of these things, and this one was in such great condition (and at the right price) i just couldn't say no. I took off the back cover to figure out the model number/year/etc and found this:

Model 2RP679
Serial 926194
Year: 1967
Chassis either A57502 AC or 703119 1
(I sent this info to the guys at justradios.com but they don't have a schematic. )

Here are some pictures on flickr: http://www.flickr.com/photos/jbuckmaste ... 2078217674

Everything works as far as i can tell, but there is a loud hum that plays regardless of whether you are listening to the radio or a record (I found a replacement needle at radio shack per the suggestions here on this forum. Thanks!). The hum is a little bit louder in the left speaker than the right one, but it is loud enough to be pretty distracting and annoying.

So what to do? I've seen a lot of posts on this forum and elsewhere about doing a "cap job" on these things to get them running in tip-top form, but I haven't seen much in the way of how to actually go about this. As in, I know I can order the caps from justradios.com or eleswhere, but then what? I'm pretty new to tinkering with electronics, but I've heard that there can be some danger involved when you're dealing with capacitors and/or power supply issues. Is there a good site or tutorial that really explains how to replace these caps, or at least will explain, in semi-plain english, how to avoid electrocution?

I will greatly appreciate any help you guys (and gals?) can give me!
Thanks!

Congratulations and welcome. My suggestions:

Go back to JustRadios. They have links to areas that can help. You can try www.philcoradio.com , audiokarma.org. Also use your search engine. You can also check out the archives here.

Thom

It looks like you got one of the last Collaro Conquest type record changers that can take odd sizes, instead of the later 3-size Micromatics. 1967 was the year they started changing to the new one.

OMG!!!

You got one of those Astro-Sonic 100's that really kick butt. I don't know what the differences are but I have a 1-RP679, the "Francisco" that was featured in a 1966 brochure. It was available in Warm Maple and listed for $650. You certainly got no Cheapie!!!

Oh, wait...I have a few pages here from a Magnavox service manual, 679-1, issued January, 1968 for the 1-RP679 and 2-RP679. The both use the A575-02-02 Amplifer and the 1-RP679 lists R207-01-20 and R216-01-AA radio chassis, while the 2-RP679 uses either an R218-01-AA or R218-01-AB. I also have a very low cut Astro-Sonic 100 "The Santiago" that uses similar components.

Your picture of the amp shows the blue and black Caps on the far right. Those are the things that need replaced, probably way out of tolerance. You desolder those from the underside and pull them out on top. The values/voltages are listed right on them and when replacing, make sure you have the + and - correct before resoldering them to the board, which is labeled.

If you've never done this before, get someone to help you or take it somewhere to get it repaired. While you're at it, remove the separate radio chassis and get it recapped, too. All the input signals pass through there before going out to the power amplifier. Hopefully, everything else is fine. These beasts really rock when you give them some TLC and a little tuneup. Just my two cents. --BB

Bobby Basham
Tucson, Arizona