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My first Recap/Rebuild: A Sansui 1000A. What bench equipment will I need?

angelaudio

angelaudio

Super Member
This will be my first attempt at recapping and servicing a tubed unit and I need some advice on what test equipment I will need to do the job properly and safely.

I already have:
Screwdrivers
Wrenches
Needle Nose Pliers
Wire cutters
Weller WLC100 Soldering iron
Kester 60/40 solder
Solder sucker
Small solder smoke fan
Solder wick
Paste Flux
Harbor Freight multimeter

I have the patience to take my time doing the restoration which I will document in another thread, so the point of this post is just to get the right equipment to be able to do proper measurements and testing once the ‘Sui is on the bench. I’ve seen some modern test equipment units that have a lot of features on them, anybody have experience with them?

TIA
Ernie
 
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angelaudio said:
This will be my first attempt at recapping and servicing a tubed unit and I need some advice on what test equipment I will need to do the job properly and safely.

I already have:
Screwdrivers
Wrenches
Needle Nose Pliers
Wire cutters
Weller WLC100 Soldering iron
Kester 60/40 solder
Solder sucker
Small solder smoke fan
Solder wick
Paste Flux
Harbor Freight multimeter

I have the patience to take my time doing the restoration which I will document in another thread, so the point of this post is just to get the right equipment to be able to do proper measurements and testing once the ‘Sui is on the bench. I’ve seen some modern test equipment units that have a lot of features on them, anybody have experience with them?

TIA
Ernie
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Is it a known good/working unit that you plan to refresh or does it have issues? If it has issues, are any of them tuning/RF related? Front end repair/diagnosis/alignment is a whole new ballgame in equipment $$$'s and knowledge.

For tools, make sure your screwdriver is JIS and make sure some of your needle nose/wire cutters have strong stubby tips because unwrapping leads from terminal strips can be difficult. Make sure you have an awl or a strong pick to pry wires. I'd also make sure you have an Optivisor and a portable LED light. For solder wick, buy the best brand you can find (Chemtronics) and get the widest style they offer. Don't buy no name solder wick!! In my limited experience, a desoldering station works best for solid state but solder wick works best for tube. Manual pump solder suckers aren't the best for desoldering in tight spots.
 
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a decent voltmeter is an absolute need. I wouldn't trust one of those HF meters poked into high voltage, and I don't think they have a 10M input either so the readings in certain cases won't jive with schematic voltages taken with a VTVM.

beyond that it depends what you are planning to do. If you want to align the tuner you need a proper signal generator. Honestly in most cases unless someone has tinkered with the adjustments, you can probably just leave it alone and have the tuner function acceptably so long as the tubes aren't dead.
 
davefr said:
Is it a known good/working unit that you plan to refresh or does it have issues?
Click to expand...
@angelaudio
This. If it's a working unit go ahead with the rebuild. If it's not, best to fix it first. Too many horror stories about folks attempting a rebuild in hopes that a unit will work after, only to introduce new issues that compound the troubleshooting process.
 
Don't forget enhanced vision, if necessary.

If you can't easily read the values on the smallest electrolytic caps and board markings with the light available, add lighting and add magnification. My dad gave us Opti-visors and I didn't use mine for a good 15 years. Now it is on my head when I'm working on gear.
 
Ray Gianelli said:
@angelaudio
This. If it's a working unit go ahead with the rebuild. If it's not, best to fix it first. Too many horror stories about folks attempting a rebuild in hopes that a unit will work after, only to introduce new issues that compound the troubleshooting process.
Click to expand...


my only somewhat-counter to this, the caps used in Japanese tube gear are pretty horrible, so don't be too surprised if it doesn't work properly because of them. The paper in oil caps are pretty much guaranteed to be leaky and that causes a lot of trouble, especially with the output stage.

I still tend to bring things up slow and do a basic function test before touching anything, but watch the output tubes very closely and be prepared to shut it down if the plate structure starts to turn red or if smoke comes out of anywhere.
 
davefr said:
Is it a known good/working unit that you plan to refresh or does it have issues? If it has issues, are any of them tuning/RF related? Front end repair/diagnosis/alignment is a whole new ballgame in equipment $$$'s and knowledge.
Click to expand...

It’s a mint unit that’s been in a box since the late 60’s so I’m unsure if it has any issues. I don’t want to power it up, I’ve read a few threads on here about this particular unit’s Suzuki PÍO caps being bad.
 
gadget73 said:
a decent voltmeter is an absolute need. I wouldn't trust one of those HF meters poked into high voltage, and I don't think they have a 10M input either so the readings in certain cases won't jive with schematic voltages taken with a VTVM.

beyond that it depends what you are planning to do. If you want to align the tuner you need a proper signal generator. Honestly in most cases unless someone has tinkered with the adjustments, you can probably just leave it alone and have the tuner function acceptably so long as the tubes aren't dead.
Click to expand...
I would like to get it to be fully functional, but if I could just get the amp section working fine for the time being I would be fine with that. I have seen a video or two where this unit is shown with the FM section showing little to very little drift, so I’m hoping that’s the case with mine.
 
Ray Gianelli said:
@angelaudio
This. If it's a working unit go ahead with the rebuild. If it's not, best to fix it first. Too many horror stories about folks attempting a rebuild in hopes that a unit will work after, only to introduce new issues that compound the troubleshooting process.
Click to expand...
I haven’t attempted a power up. Under the chassis everything looks good, nothing looks blown or burnt
BF3FDC04-B77C-424F-8562-C24D0D8508CA.jpeg
 
angelaudio said:
I haven’t attempted a power up. Under the chassis everything looks good, nothing looks blown or burnt
View attachment 2710204
Click to expand...
Appears to have a single bias adjustment pot for the 7591 output tubes, later ones had one per tube (you want that). A modification to consider once you get in it. However, if it's had so little run-time on it over the years, why not find a variac & power it up SLOWLY, like in small incremental steps over a day or 2. It may just awaken just fine, as any heat-related component aging should be minimal.
 
Catmanboo said:
Appears to have a single bias adjustment pot for the 7591 output tubes, later ones had one per tube (you want that). A modification to consider once you get in it. However, if it's had so little run-time on it over the years, why not find a variac & power it up SLOWLY, like in small incremental steps over a day or 2. It may just awaken just fine, as any heat-related component aging should be minimal.
Click to expand...
Would any variac do? I’ve seen some at my local electronics repair shop for anywhere between $75-$150
 
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