• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Fair price for a 9090 with iffy channel?

Also, when I'm looking at solder connections, I should be looking for something that is cracked or disjointed looking? What about a perfectly circular hole in the center of the blob of solder?
 
Doc, if you have the face plate off, the tuner comes off with 8 screws. Then you have access to the push switches. Sounds like it's just a matter of preference.

akahn, the speaker protection relay is a small, roughly onench squarecube with a clear plastic cover. It should be fairly obvious from the bottom. It's always a good ideal to look for broken or cracked components. As far as you discripion of a blank hole that may or may not mean anything. It depends on what and where it is.

- Pete
 
LBPete said:
Doc, if you have the face plate off, the tuner comes off with 8 screws. Then you have access to the push switches. Sounds like it's just a matter of preference.



akahn, the speaker protection relay is a small, roughly onench squarecube with a clear plastic cover. It should be fairly obvious from the bottom. It's always a good ideal to look for broken or cracked components. As far as you discripion of a blank hole that may or may not mean anything. It depends on what and where it is.

- Pete
Click to expand...

What do you do about the dial cord, Pete?


Also look for dark rings in the solder encircling the pin of a component. Solder connections should be shiny, not grainy.
 
Warren, the dial cord stays in place on the dial face. The whole assembly, including the dial face and cord comes off on a sub chassis. It's a piece of cake. Next time you have an 8080/DB or 9090/DB open take a look at the tuner assembly. At first it looks pretty intimidating but you will see it is very well laid out for easy removal. I'll try to find a picture.

- Pete
 
akahn said:
Well, I picked up this unit today and the right channel wasn't working, but when we turned up the volume, some scratchy sound came in. I took the top off... now how do I get at these pots? Can someone direct, me please? (I've only done this once before.)
Click to expand...

Did you get the speakers too?

Search the archives for cleaning tips - lots of old threads about cleaning pots and switches.
 
I forgot to mention that the meter for the right channel shows no activity while the left one shows plenty... except for an occasional and slight blip when shutting the receiver on or off. Maybe this info will help.

I've flushed out the pots a couple times now. I'll try some more, but I'm thinking more and more that this isn't a dirt and grime problem... the next step is searching for broken solder joints, right? Are there certain areas I should be looking at first or a certain path to follow? Now's the time to buy a service manual, isn't it?

Also, there are many fuses inside. How do I tell if the type of fuse with a flat piece of metal is blown? The ones that are just filaments are all fine, but I've never seen the kind with a flat piece of metal.
 
LBPete said:
Warren, the dial cord stays in place on the dial face. The whole assembly, including the dial face and cord comes off on a sub chassis. It's a piece of cake. Next time you have an 8080/DB or 9090/DB open take a look at the tuner assembly. At first it looks pretty intimidating but you will see it is very well laid out for easy removal. I'll try to find a picture.

- Pete
Click to expand...

I sure will! Maybe I'm the one doing it the hard way! :banana: I figure anyone who could come up with the relay opening tool must be onto something! :naughty:
 
Yeah, I actually did that before I got any advice here, and it worked pretty well. It seemed designed to allow easy removal of the whole upper part. Now, to get at that relay... how on earth do I remove the cover? Do I need to push in on the two little holes on the outside of it? Or do I just need to look through to verify that nothing is melted, burnt, broken cracked? Because everything appears to be fine.
 
Last edited:
Akahn, The function switch and tape monitor switches are the most likely culprits, these two switches are on the circuit board at the right rear of the unit, you can see them with the top off. Spray the switches with de-oxit and operate them several times throughout there range. These switches oxidize badly.

Don't go cheap on the cleaner use De-oxit, it is the best and IMHO the only stuff to use on vintage equipment.
 
Alright, now I've cleaned this thing out several times with DeOxit, and still not a peep from the right channel, not a hiss or a crackle. Is it likely something more than dirty switches at this point? If so, what's the next step to take? (BTW, I'm still curious about those fuses: what do the fuses with flat pieces of metal look like when blown?)
 
First grab the relay and wiggle it and see if the channel comes in. If it does the relay needs cleaning. If it doesn't, the problem is probably elsewhere.
LBPete has invented a tool to get the relay cover off without desoldering the relay. You can search for that thread or wait a minute, I'm sure Pete will be back here to tell you how to do it.
Otherwise You desolder the relay then put a very small screwdriver under each side of the cover at the holes, and pull the cover off. then clean the relay contacts with a piece of paper soaked in alcohol. Put the paper between the contacts then draw the paper through the contacts while holding the contacts closed with your finger. Repeat several times.
Is this a 9090dB?
 
Here's a link to the relay cover shucker post. Relay Cover Shucker
They do take a little finesse to use. Basically, you work the edge up between the cover and base just below the pegs on the base that hold the cover on, then lever the edge of the cover over the pegs by moving the tops of the tool away from the relay. You can break the cover with this tool if you are not careful. (don't ask how I know)

If you want to make these things, you need a vise, a big hammer and a piece of something hard to use as an anvil to form the hook. I used a piece of steel strap and bent the sheet metal over it to form the hook. If there is any interest, I'll make another pair and post pictures of the bending process.

- Pete
 
You must log in or register to reply here.
Back
Top Bottom