SX-1250 Stabilizer Assembly AWR-106 Needed

[mdemott]

Hello:

I'm not sure this is the right place to post this so redirect me as needed.

I am doing another SX-1250 rebuild and the Stabilizer Board has a ton of lifted solder pads and well.....it's a mess. Lifted traces, etc..... clearly some bad workmanship given how many issues there are.

I checked ebay and struck out. I'm looking for a replacement board. Any thoughts on a good parts source or perhaps someone here has one we could work a deal on? This is a receiver for a friend and not one I'm rebuilding to sell.

Any thoughts are appreciated.

Thanks.

 

[embrown057]

Hope you can find a replacement, may be difficult. In the event you don't you can contact: http://www.circuitrework.com/
They have done a few boards for me (my customers) with perfect success. In fact you can hardly tell they have been reworked, they do stellar work.

 

[mdemott]

This is what I'm dealing with. Looks worse in person than in the picture.

 

[embrown057]

I've sent them a lot worse. Before the birth of the new SX1980 power supply boards I had to deal with cleaning up trashed boards, yes worse than yours. I still from time to time have to either find organ donor unit or send the boards out, witch ever is more economical. I completely de-populate the board before sending it out, who knows what's under the rest of the solder.

 

[tsd71]

That board can be repaired, if you decide to trash it let me know.

 

[rcs16]

I agree the pcb can be made to work, ugly as it is. Basically use the new or existing component leads to act as the new traces, following the same path(s) as original, form the leads in a circle, to act as pad, leads/traces glued in place etc. tedious work.

If there is enough interest, I could re-design a new pcb. Since I do not own a sx-1250 myself (only a transformer) I would need an old pcb (preferred) or all the mechanical details in order to duplicate the design.
Let me know if you are interested. I'd have to think about how much I'd charge for a new blank pcb but it would be probably somewhere between $50-$100 for a blank. I would probably beef up the heatsinks as I did in the sx-1980 pcb, replace the old Toshiba rectifiers with a modern bridge.
Once I am done with the old pcb, I can send it too tsd71

Cheers
Rick

 

[mdemott]

That’s an interesting thought. I’ll see how it works out trying to find another first then chat with you about your thought. I like that idea.

 

[tarior]

I agree the pcb can be made to work, ugly as it is. Basically use the new or existing component leads to act as the new traces, following the same path(s) as original, form the leads in a circle, to act as pad, leads/traces glued in place etc. tedious work.

If there is enough interest, I could re-design a new pcb. Since I do not own a sx-1250 myself (only a transformer) I would need an old pcb (preferred) or all the mechanical details in order to duplicate the design.
Let me know if you are interested. I'd have to think about how much I'd charge for a new blank pcb but it would be probably somewhere between $50-$100 for a blank. I would probably beef up the heatsinks as I did in the sx-1980 pcb, replace the old Toshiba rectifiers with a modern bridge.
Once I am done with the old pcb, I can send it too tsd71

Cheers
Rick

The service manual has the board layout.

 

[rcs16]

The service manual does not have, nor should have, the dimensional information that is required to make a board outline, the slots/cutouts, pin spacings, hole sizes etc for those connectors.
Those connectors are imo long obsolete, thus would have to be re-used/transferred over or replaced with something else, if so, then the plugs would have to be re-wired to use the new mating plug(s) to interface with the new connectors. It's all in the details.

 

[tarior]

I once made a driver board for a Sansui BA-5000 by enlarging the SM picture on Zerox (this was like 15 years ago) so that I could do the mask more easily, then shrank it back down and copied the mask onto clear plastic in order to develop and etch the board. It worked great. I guess I did have an original to compare with for size.
I can measure the dimensions of a stabilizer board for you if you would like.

 

[tarior]

Totally done the old-fashioned way.

 

[rcs16]

Nice work on the BA-5000. I have done that in the past too, use something, such as a 8 pin SIP as a reference to scale against if I did not have a pcb to use as a reference.
Thx for your offer
lets wait to see if anyone is interested first before we go forward.
In the past when I did pcb layout, I'd get a mechanical drawing from the Mech Eng(ME)

 

[tarior]

Thanks. I'm amazed that I could still find that mask. I swear that I could lose an elephant in my shop.
You may not get a lot of takers on a replacement stabilizer board. They really aren't that hard to fix.
The reason for the Sansui board was that the original had been physically broken by a less than competent repair shop.

 

[rcs16]

I'm amazed that I could still find that mask.

I hear you, sounds like you are organized.
It is fair bit of work for not much return. We'll see if I can even unload those sx-1980 PS pcb's, certainly not a big $ maker. probably should be spending my time on something that I can sell in more volume. Any ideas, PM me.

 

[zebulon1]

If there is enough interest, I could re-design a new pcb. Since I do not own a sx-1250 myself (only a transformer) I would need an old pcb (preferred) or all the mechanical details in order to duplicate the design.
Let me know if you are interested. I'd have to think about how much I'd charge for a new blank pcb but it would be probably somewhere between $50-$100 for a blank. I would probably beef up the heatsinks as I did in the sx-1980 pcb, replace the old Toshiba rectifiers with a modern bridge.
Once I am done with the old pcb, I can send it too tsd71

I'm in as an investor!
"Tarior" old school repair is a viable method for one off needs, but the idea of a more modern design, addressing the heat and regulation would be interesting to see. A board that could reuse the original Molex connectors.

The return on investment is minimal but the rewards comes when another piece of well designed equipment is producing its intended effect.

 

[tarior]

Well, the 1250 board isn't anywhere near as bad as the 1980 board, though it does run hot. A few extra heatsinks and upgraded transistors is about all that one needs.
The old fashioned way would work even to re-use the Molex connectors, but yes, for any kind of quantity greater than one or two, it's not at all viable.

 

[rcs16]

A lot more 1250's out there for sure, still very limited.
As for the pots, I think gone or stuffing option, on the 1980 the +/- 80 are withing 300mV, precision components these days.
In the old days, not so long ago, before the Chinese mfg's, to get a pro pcb made was very expensive, since they charged you heavy for NRE setup charges and you had to run a whole panel usually 18"x24", now with batching the costs are significantly reduced.

Sorry mdemott, we are trashing your thread, I am done unless you ask more ?'s about your specific issue at hand. Obvious it would be cheaper to get a used pcb, but they are few and far between, it could be next week or next year+, it is hard to say, but I think I can say that a new re-design could potentially be much more reliable and better performing as I'd mod the design a bit.

 

[mdemott]

No need to apologize. This is good stuff and I honestly think doing a new board is something that should be looked at. Was going to PM you about it next week when I'm on the road for work. This receiver is a very important item for my friend as he bought it 'new' in college. When we pulled the cover off there was markings on this board numbering where the plugs went, etc... someone had been in there before. I did a restoration of the unit and tried to work with this board the best I could. Receiver worked beautifully for many hours of listening and then it popped fuses 1 and two on the 107 board. Checked for anything visual and didn't see anything so replace fuse and hooked up to DBT and it didn't work. I told him I really want to find a repair or replacement for the 106 board before we dig deeper. My gut tells me that board still has issues and I want it done right.

Really appreciate you guys talking through this. It has more meaning than me trying to restore something I bought or found for purposes of selling and making money. My buddy was practically choked up when his baby was working again. Feeling really disapointed and responsible for the fact it didn't hold up.

 

[tsd71]

Nice work Rick, Geez while you are at it how about an SX-1010 power supply recreation. I've worked on many where traces were all but gone, and boards were cracked from the heat. Pretty sure slightly easier than the 1980 and the 1250 stabilizer.

 

[rcs16]

Hi tsd71,

Thanks, yes the 1980 was the biggest of them all, so the rest are all scaled down versions. That makes it easier for me since the bulk of the work has been done.
None the less, it is still a fair bit of work, regardless of the pcb complexity, I have no guarantee's that I'd ever be able re-coupe my development efforts. The more interest/demand the better for all.
Thus, I need a old pcb or a detailed mech drawing in order to make/transfer the physical/mechanical measurements in order to duplicate the pcb's physical dimensions exactly.
I am willing to work with folks like you that ask for these items, but need assistance such as having an old card to work from and input as to changes to improve the design.
So if you or anyone else wants to work with me, pls PM me and we can see what we can come up with.

Rick