CA-3000 mild Pop

johnny_fever

Sansui Addict. No Serious. Not Kidding.
Subscriber
Hi Guys,
My CA-3000 has a mild pop (L Chan) Since is was being looked at we decided to re cap it. Tech felt it was the caps anyway. well it started popping again when I got it home. I decided to open it up and solder the pass through's (Real Fun) well the tech lives 100 miles away & I refuse to ship. So do I wait till it breaks or do I subject the poor tech to chasing a ghost?

Symtoms
Pops while warming up. 15 min to 1 hr never the same time & only once.
Pops in FM, AUX, Phono,
 
Last edited:
Providing it is a mild pop as you say - be nice to your tech. :smoke:

If it gets any stronger or more frequent, then review the situation, gaining intelligence on how this behaves is key to tracking it down.

You could try gentle pressing on the PCB's with a non-conductive tool, or a can of freezer spray and hit each transistor in turn, in the offending section (L) with a minute or two gap between each squirt.

Good luck :thmbsp:
 
Im going with the leaky transistor theory......

Can of freeze spray could help you find which one it is as John says.....
 
Those things are a mass of interconnected PCBs. Could be any of the connections between the edge connectors, etc as it moves while warming up.

IOW, might not be a component but a physical malady. I rebuilt one of those for Frank in New York. TonsOFun
 
Thanks Guys.
The CA-3000 is totally loaded with PCB's and a double sided main board. I can see over the years how techs described this unit as being busy. Must of been ahead of its time compared to other Sansui stuff of that time. Thanks Rick
 
Well Its popping again. The tech repaired It last by re soldering some large pins that attached to some connecters. No Transistors were replaced. This fix lasted a long time. Since I posted this In 2012 what have we learned about the popping In CA-3000's? Thanks Fever
 
Last edited:
Couple of things going through my 2.....I had random popping. I commented about the black oxidation on the leads, so all the boards I re capped I went through a little clean the leads experiment.And didn't not have the popping anymore. 2) I had thudding and that was power supply caps, the transistor caused pop was very sharp, very fast more of a SNAT... On my AU-9900 I tried the cleaning, but to no avail. I had to replace the device (s)
 
I already cleaned all the pins and connecters. Having worked on lots of G 8's & 9's I have witnessed the black oxidation. Thanks
 
<snip> very fast more of a SNAT...

A 'SNAT' (great word) :banana: jumping jehosephat, it's a long time since I heard one o'them! :D

Sorry about the continuing difficulties Johnny F - the fix that lasted a long time - maybe you touched something close to the problem?
 
Last edited:
Hi,

I'm afraid your CA3000 may also have leaky transistors. The 2SA726's and 2SC1313's are notorious for that. The black corrosion gets inside the transisitor, and it starts cracking. Popping however, is mostly caused by leaky caps. I did a CA3000 recently, and it's a great piece of equipment, but very, very time consuming if you want to do it right. I did a full recap of tone control, low and high filter board, including swapping all transistors. I also found a factory fault, of of the supply boards wasn't adjusting to spec value. Two wrong transistors where fitted. I could compare, because the CA 3000 has two identical boards. I changed it, and after that it dialed in just fine. Also the irritating popping noise when operation the input selector (aux/tuner phono), was gone.

Good luck,

Nico.
 
It was re capped. Still popped. Returned to tech. He re flowed the pins. It worked excellent for a year. Funny It has the same symptoms again. pops once or twice In the first 20 min. Then Its fine. Now I just turn It on ahead of time. It will be a good winter project. Thanks Rick
 
Mine was doing that as well. I replaced all the caps and transistors. Still did it, found some bad traces on the high/low filter board and redid the (previously redone) pass throughs. Solved. Use a magnifier when examining the boards as you can't see this stuff with the naked eye.
 
There are over 100 pass throughs (They are called vias) in that thing.
Some are hiding under tape near the connectors.
Some a tucked in next to controls.

To fix them right, you need to suck them out, make a short piece of wire, scrape the trace on each side, insert wire, bend it to the cleaned trace and solder it down.

Until the traces are straightened out, all bets are off.

While you're in there, shotgun all the suspect transistors.

It takes about 20 hours to go through it (more or less).
 
X2 on what blhagstrom stated above. I purchased mine last month and someone had previously worked on it. (Really poor job) they literally cut wire and just stuck it through the holes without bending or connecting to the traces. Might as well have soldered random wires to the top of the lid and sacrificed a chicken while doing a rain dance. I spent a week slowly rebuilding the unit in the evenings. All new transistors and caps.
 
Thanks for all the ideas guys. I will have the wife pick up a live chicken on the way home tonight. Thanks Fever
 
Johnny it's divide & conquer time....
A do you run with the EQ in ( and or ) the filters?.

If yes, turn each off for a few operation cycles and see if the POP goes away?
My AU-9900 ONLY snatted with the EQ in.. which made the trouble shootin easier...
 
Another thing not to overlook is those molex connections particularly the thin wire ones that attach to the volume control board. One I had thought and looked fine (one of which I did not have to make or replace) turned out to have a broken wire inside the jacket before going into the crimped pin. Do not ever pull/tug the wires to remove the connectors from the boards. Can't believe how many people do that since they cannot get hands on the connectors themselves. I'm positive that's where 90% of the damage in my unit was from.
 
Thanks Guys.
For now Im just turning It on beforehand. I will make time soon. Thanks
 
Back
Top Bottom