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The Official SENCORE LC103, 102, 101, 77, 76, 75, 53 thread.

Bill Ferris said:
Are you asking me are the displays back lit ?
No, I don`t think the LCD are back lit, though I`ve never tried to operate test equipment on my bench in the dark, especially the Sencore LC-103 while testing capacitors !

I have never have, or needed to have opened up my LC-103 in the 33 yrs. of ownership/use.

IMPORTANT EDIT: !!
My Sencore AUTO Z is in fact a LC-102, NOT THE "ASSUMED" 103 model that I thought I owned, visually confirmed, after I went out to my work shop and looked at it on my very infrequently used secondary repair bench, just now !

I profusely apologize to all thread participants/readers for any model confusion caused by me not checking & confirming before engaging in this thread !

My only "lame/halfass" excuses are that I retired from commercial/public servicing audio electronics in 2002, and I`m currently 70 yrs. old !
Mercy Sakes Alive, its Hell getting old !
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lol no problem at all, I’m in my early 40s and I can say that I have those exact same moments. “Wait, what?…. I could have sworn…”. I just hadn’t seen a 103 with an LCD screen before, so I was very interested. It’s on your desk that isn’t used frequently? So I take it you don’t use the 102 very often? I was curious how often I would use this 103, the last few days I have been using it a lot, a lot. Once the new toy feeling wears off, then I will see.

Dan
 
saabracer23 said:
lol no problem at all, I’m in my early 40s and I can say that I have those exact same moments. “Wait, what?…. I could have sworn…”. I just hadn’t seen a 103 with an LCD screen before, so I was very interested. It’s on your desk that isn’t used frequently? So I take it you don’t use the 102 very often? I was curious how often I would use this 103, the last few days I have been using it a lot, a lot. Once the new toy feeling wears off, then I will see.

Dan
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Well I`ll say this, every few yrs. I reform my stock pile of new and older HV capacitors leftover from my 5 music store and walk in repairing clients/customers.
But I tend to use my Heathkit HV (max ~ 425 v) variable bench power supply that I bought and built in the very early nineties using a 10k ohm 2 watt resistor in series as I slowly raise the PS`s output while watching its current meter, and if appearing heathy, I leave it energized for a few minutes before moving on to discharging and the next cap.

This seems to be faster than using my "LC-102, in which I then use for testing any higher voltage electrolytic/oil caps since it can test up to 999.9 V. and provide me ESR & leakage at those HV testing ranges.

For lower V. electrolytic caps. I tend to use my several very handy portable Peak brand capacitor checkers, and a very handy LCR component tester ( my first Peak tester purchase in the early 2000s)
 
I found some info on batteries for the LC102 (and probably other models) that may be helpful. I haven't done detailed measurements yet, to make sure it will fit, but it appears that an ES2.3-12V battery will work in an LC102. It will need a ZA5350-B clip with an appropriate DC connector added to fit whatever your meter requires - mine has a standard DC barrel connector measuring about 3.0 x 6.3 mm. I'm not sure if I'll add a battery or not, but thought I'd document the info for posterity. . . .

Edit - I looked at the battery compartment on mine and the dimensions will be fine. It's shorter, though so may need a piece of foam on the end to keep it from sliding.

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Richard P said:
I found some info on batteries for the LC102 (and probably other models) that may be helpful. I haven't done detailed measurements yet, to make sure it will fit, but it appears that an ES2.3-12V battery will work in an LC102. It will need a ZA5350-B clip with an appropriate DC connector added to fit whatever your meter requires - mine has a standard DC barrel connector measuring about 3.0 x 6.3 mm. I'm not sure if I'll add a battery or not, but thought I'd document the info for posterity. . . .

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Awesome research Rich !!!

Good to have that info here!!

I added it to the first post.

Nashou
 
I powered up the 'parts or repair' LC102 this morning using my bench power supply set for 12V, 2A and the battery connector. It fired right up. Whoo Hoo :banana::banana:
I have a 12V, 2.5A wall wart power supply that I'll probably attach the proper DC connector to and just use that to run it until I can track down something with the proper 3-pin DC connector for the external, 18V power input.

I don't have the proper test lead yet, but the ebay one should be hear early next week. I tried calibration with a BNC to mini grabber lead I have and it passes for open circuit but fails the short circuit test with a brief 'error 4' message that clears after a few seconds. We'll see how it does with a proper test lead. Mine has some holes already cut into the top of the gray relay, so maybe I'll give it a squirt of contact cleaner while I wait. . . . I assume that's what the holes were created for.

More to come.

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I'm building a power supply for my LC102 and needed a source for the 'mini IEC' plug - the 3-pin plug that was used on the original PA251/PA252. I found that there are quite a few power supplies out there that use the same mini IEC so I thought I'd compile a list to make your search easier. I bought a Hypercom WLT-2408-C but any of these should work. Do some research to make sure all three conductors are present (not just 2 of the 3) and it has the correct mini IEC plug. Of course you'll need to connect the cord from one of these to a suitable power supply with 17~18VDC and at least 1 amp and the proper pinout:

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  • Hypercom SNP-K039-H
  • Hypercom SNP-Q319-H
  • Hypercom SNP-T109
  • Hypercom WLT-2408-C
  • HP 61221 power supply
  • HP CD-Writer 4400 8200 9200 9600 Series, CD4E series & other HP CD/DVD writers with 5V/12V dual supply
  • DSA-0301-05 (some use a round, 4-pin connector)
  • Hayes 52-00005 (may have only 2 wires connected . . . check)
  • Philong PSA15-201 (some use a DIN 5-pin connector)
Still not certain if a 19VDC laptop SMPS will work OK to replace the 17VDC/18VDC original supplies, but there are lots of 18VDC SMPSs out there if needed. Anyone have experience with a 19VDC supply? I have a bunch of those so it would be nice to use one rather than buying something.
 
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I'd like to calibrate my LC-102. I don't have the precision capacitors and inductors suggested in the procedure doc. Does one just source these from Mouser \ Digikey individually? Anyone here already assemble a kit?

I kind of assume anyone offering calibration services online behind an "Inquire For Pricing" button is going to be chancy and pricey at best.

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Any of you have an original PA251 power supply or one of the Choice SMPS supplies that you would be willing to measure the output voltage on? Preferably loaded . . . I suspect the PA251 outputs more than 18VDC since its a simple transformer and rectifier/capacitor with no regulator. I'm building my own supply and was thinking to use a laptop 19V SMPS since I have a bunch of those, but don't want to damage my LC102 in the process. Worst case, I can probably find an 18VDC SMPS, I suppose.
 
Why not just add a series diode and drop 0.7V? That seems close enough to 18VDC.
 
That might work, if i truly need 18VDC (maybe 2 in series). Thanks for the idea.
 
Mine was missing the power supply, battery, and rear panel. Instead of buying/using the 18VDC adapter which is intended to both operate the unit and charge the battery, I made a rear panel with a DC jack, connected it to the 12VDC portion of the circuit (bypassing the charging circuit) and operate the unit with a 12V power supply. Works perfectly and since I don't need the battery, it was a lot less expensive for me to get this unit operational.
 
Also, the PA251 seems to have been made in two configurations; a square shaped unit outputting 17VDC at 1A, and the rectangular one on the auction site at 18VDC/1.5A. That ambiguity is what pushed me to my solution above. If I were going to use a 19V PS with high current rating like most laptop supplies, I'd put in 2 series diodes to at least split the difference between the nominal 17/18V ratings of the two PA251 supplies.

The interesting thing is the LC102 has onboard regulators - one of which is 18V. Not sure how it has the headroom to function if the incoming voltage is at or below that level. Haven't given it any thought in the several years since I got my unit.
 
On my adapter output is 20.76 VDC at the specified 117VAC input. Output is 21.32 VDC at 120 VAC input.

Sencore.png
 
GKTAUDIO said:
I made a rear panel with a DC jack, connected it to the 12VDC portion of the circuit
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I've done this already with a 12V, 2.5A SMPS and it works well, but I may add the battery so I want the external supply as an option for power. I'd be curious to see how hot the diodes would get. By my math, 0.7V @ 1 amp is 0.7W - i'll hook some up to my bench supply to see . . . a standard 1N4007 is good to about 3W i think.

ogodei said:
On my adapter output is 20.76 VDC at the specified 117VAC input. Output is 21.32 VDC at 120 VAC input.
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Thats about what I expected with the simple transformer/diodes/capacitor configuration. Thanks @ogodei
 
Richard P said:
Any of you have an original PA251 power supply or one of the Choice SMPS supplies that you would be willing to measure the output voltage on? Preferably loaded . . . I suspect the PA251 outputs more than 18VDC since its a simple transformer and rectifier/capacitor with no regulator. I'm building my own supply and was thinking to use a laptop 19V SMPS since I have a bunch of those, but don't want to damage my LC102 in the process. Worst case, I can probably find an 18VDC SMPS, I suppose.
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I have the Choice. 18.38 loaded and unloaded.
 
Thanks @bobgroger . I appreciate you taking the time to check it. I'm still on the fence, but because the PA251 output is so high, I'm pretty sure I'll go with a 19VDC supply, assuming that's what it's actually producing. I won't get around to building it for a while, so I'll keep my eyes open for an 18V SMPS in the mean time . . . . not that common but they are out there.
 
Quick update on my bargain LC102 - everything is working well. I built a 12VDC power supply to run it off the battery connector, cleaned the 2 large relays and cleaned all the board connectors and input BNC/Fuse while I had it open. The large, white relay was pretty clean but the smaller one with the clear cover was reading in the 10s of ohms. It now calibrates for open/short with the Ebay test lead and reads capacitance, ESR and leakage perfectly on a variety of parts I tested. I'm still collecting the parts for a proper external power supply and will run through some more extensive tests in the coming days but I'm pretty thrilled. Mine was last calibrated in November, 2022, so I'm thinking it will be good without further adjustments . . . . we'll see.


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