1000a again

I made a big mistake in trying to change the coupling cap hooked to the 12ax7
I thought it was a .33 and it was a .003 . Now I have no right channel.
I hooked the right ones back up. It seems I have signal from that 12ax7 forward.
I didn't smell any burning smell or anything.
Could that have messed with a wiper or something?

What is a 100a ?

1000a??

ops yes 1000A

shawn. Back up, slow down, start over. Which tube EXACTLY. What pin was the cap on, and what was the value of the original and the value of the one you replaced.
and then step by step detail exactly what you did and what happened with the unit.
I presume the 1000A was running before this excursion into the AUDIO VACUUM?

The more detail, no matter how silly sounding to you, the easier it is for us to troubleshoot and help diagnose a problem. The only DUMB QUESTION is the one you DON'T ASK. We've all BTDT. Most of us have the T-Shirt. Some have read the book, and watched the Movie.

The only .003uf cap (C-96) in that area is in what's known as a Packaged electronic component or PEC(CRS-02). One of those Tan squares with 3 to 10 leads that looks like a ceramic cap on steroids. And you can't replace it with out ripping the PEC out and buildin a new one on a board. There is a .03uf (C-99)between V14 (12ax7)and a PEC (CRS-10A). I don't think the replacement with a .3uf would cause a loss of channel however, under ideal conditions (ie: no leads are crossed, or miswired).

Check for
1.) Flying leads touching other area that they aren't supposed to. like the chassis or another cap or resistor.
2.) Solder bridge between tube socket pins where the part connects to.
3.) Solder bridge between terminal strips where the part connects to.

The Sansui 1000A is really a triple canopy jungle underneath. You need to be absolutely specific in details for location and part number. "a .003 cap near a 12ax7" isn't good enough, although there are only 2 12ax7's in the whole thing. Think if you had 7 12ax7's in it.....See what I mean? Use the template for future questions with regard to parts.

Copy and Fill in the blanks

Tube......

Pin # that the part connects or is connected to.......

Part # replaced

Value and voltage of original part

Value and voltage of replacement part......

Exactly what happened when you put power to it. Snaps?, Crackles?, POP's?, all of a sudden no sound?? , Smoke?? blown fuse?, house lights went dim, etc ..........

Using a signal tracer work from V14 thru the pec's, up to the 6AN8 and then to the 7591. Where you lose the signal is just past the bad component. Hopefully it's not one of the pec's. If so you'll need to build one based on the components inside the dotted lines for that part. The caps inside are pf values. The resistors are most likely 1/8 or 1/4 watt. The part#'s are listed separately in the parts list and also say they are part of CRSxxx"

Check the 6AN8's on a tube tester. You could have blown the tube on that side. OR swap side to side. Note the results.

Swap the 7591's by pairs side to side. Note the results.

Larry

ok It is pin 1 of 12ax7
voltage on good channel 130
voltage on bad channel 125
Seems I have signal from that pin on both tubes both channels .
that oil cap that caused the problem might of been bad it registers higher value.
It is hooked to a 7 wire crs 02 whatever that is.
No smoke no pop or anything else .
Just no right channel.

Did you test the 6AN8 driver tube on a tester????? If no tester swap the 6an8's side to side. Ifthe problem stays on the right, the tube is not at fault. If it moves to the left side ORDER 2 new 6AN8's. And use the old good as a spare. Get them matched if possible.


CRS 02 is your tone circuit. It may be blown internally. Everything INSIDE the dotted outline is INSIDE the PEC.
CRS 02 should be a 5 wire PEC according to the manual. , not 7 wires
Take a picture of the area and post it. They really help.

VR7 & VR8 are the Bass and Treble controls.

To test whether the PEC is BAD or NOT.

1.) Disconnect the Cap from Pin 1 (0.02uf) AT THE PEC. Leave the cap connected to the tube PIN 1.

2.) Disconnect the PEC Lead from PIN 7 of the tube.

3.) Connect the free lead of the cap in instruction 1 directly to Pin 7.


This bypasses the BASS and TREBLE CONTROLS and the PEC. This is ONLY FOR TESTING. DO NOT LEAVE IT LIKE THIS.

Power up and determine whether that side is producing sound or not. If it is the PEC is bad. (Also test the resistance of the pots. Center to outer leads. turn the knob. The reading should change smoothly. )

Power down and post the results.

The answers on your post #6 are a bit vague. Voltage WHERE?????

What value is the cap that is NOW Connected to Pin 1 of the 12ax7.

Once you've determined that the PEC is probably good, connect it back to the tube, and use your signal tracer from that point on (pin 7 on the 12ax7) to the output tube. Check all resistors by lifting one leg and testing them out of circuit (it's not make do work. yes it's tedious as hell but important. Write down all readings with the part # and the indicated value by the colored bands.

You can test CRS10A and CRS 01 bypassing them. 10A is the Low Filter and 01 is the high filter network. We;ll get to how when you get to that point. DO NOT RUSH, take your time and work methodically. Fortunately Sansui listed all the parts in them so you can build small boards with the parts on them to replace the PEC's if necessary.

Thank you I will test.
pin one is .003 and I think acording to scematic should be .002
I will test
I did switch all tubes around and problem stayed on the right channel

Ok its up and running again.
I changed those input caps on the 12ax7 to .02 orange drops (not sure but i think those caps kinda suck) both channels came up. And that CRS 02 dose have 7 wires on it I pulled it out of its little hole and counted it four times.
I have seen ones on e bay with 5 wires. don't know whats up with that.
Changed the power tubes to EH and the 6bl8's to NOS jan sylvainia. This thing took 5 leaps in sound quailty. What is a good 12ax7 to buy?
Also The K 40y-9 .33 caps are comming in the mail to replace the solens.
Should be interesting.
Thanks for your help.
Shawn

Tele's are too bright in the 1000A. The Original Equipment Toshiba were made on Mullard tooling under license and sound pretty good if you can find them. If not then a Mullard. A RCA Black plate is a good choice there in place of the Mullard.

larryderouin said:

Tele's are too bright in the 1000A. The Original Equipment Toshiba were made on Mullard tooling under license and sound pretty good if you can find them. If not then a Mullard. A RCA Black plate is a good choice there in place of the Mullard.

Click to expand...

What about any of the other Philips tubes? They should have a similar internal structure to Mullards.

12ax7

I have some rca's GE's and I orderd new EH's JJ's and sovtecs.
I will install the k40y coupling caps when they arive and then roll tubes.
I will post sound results. I can always use the leftovers for jukebox amps or future who knows.
Shawn

1000a results

After changing caps and tubes the magic combo that I liked best with my speaker is..
Auricap by Audiance .33 coupling caps
The oil caps were to big and the bass was tubby ,solens were bright
Orange drops were dull and flat.
Other caps simply woln't fit.
12ax7's best of what I tried: Sovteks were 1st
Jj's were last. RCA came in second GE's were just ok EH's were bright.
This reciever sounds absolutely stunning .
Shawn