Sencore LC102 Vs Sencore LC103 - Page 1
Forum section: electronics / beginners

author: Bill Kelso
author_rank: Newbie
timestamp: December 04, 2023, 02:17:13 am
content: Hi Guys and Gal's..(Don't know if there any here ) Just being PC. As you can see I have a Sencore LC102 & a LC103 Cap Checker. And I just picked up a Sencore LC103. I was told that the LC103 had a Problem. I did get a good price due to that. It looks brand new and looks like it has never been opened. I have it open now and just blew the dust of the IC Top side. It's very clean. I have a full complement of test gear here.So I wanted to make sure the LC103 is working and or locate the problem. So Here's the Problem on the LC103. I can't find one??? The only thing that I don't understand between the 102 and the 103 Is the Cap Leakage test.They both show that the cap is good but the way they both display it has got me wondering. I will post a pick I found on line of the LC103 in the Cap Leak Check mode. Notice that The Lower bar graph is full on to the right, And the Leakage in Ua is "0"?? But the upper right shows resistance in Ohms and it says "Good"The LC102 display shows in Ua's and says "Good". It does not display in Ohms.I'm beginning to feel that nothing is wrong with the LC103. It would be great it those of you agree with me here on this reading. I Have checked a number of caps with the LC 103 and have yet to see an indication Of Leakage in Ua's.I just happened to pop in here after doing a search on googel and ran into a thread fro 2019 about repair problems with the LC 102. So.. Gald to be here with the experts and Thankyou in Advance.I served in Vietnam thru 66-77 and when I had a Problem I always went to the Old school Sergeants to set me straight. I hope someone here can help out.

author: liaifat85
author_rank: Regular Contributor
timestamp: December 04, 2023, 10:24:41 am
content: Ok, so you were told that the LC103 'had a problem'? Didn't the supplier tell you what the problem actually was?

author: coromonadalix
author_rank: Super Contributor
timestamp: December 04, 2023, 11:29:18 am
content: normally on each start you do the 1st thing, the open and close calibration .... before doing anything elseon the internals the main pcb of the 103 is highly condensed with some i/o ic's and more evolved too for the lcd and display tests, you have more informations giventhe voltage generator pcb is supposed to be the same, it goes up to 1 kv,warning herebut i think the 103 gives an impedance measurement scale / vs leakage, but reading the user manual will tell you moreyou could ask : volvo_nut_v70 in the sell thread second pagehe as one to sell right now, he could do some "compare"

author: Bill Kelso
author_rank: Newbie
timestamp: December 04, 2023, 04:34:57 pm
content: Quote from: liaifat85 on December 04, 2023, 10:24:41 amNo I bought the unit from a seller who handles Sencore stuff. He re-ferbe's it and re sell's Sencore. He is so backed up and he had just picked the LC103 up and offered it to me cheap and will be supplying tech info on repair. He didn't have time to check it out. So I bought it. The price was very low. He used to work for Sencore back in the day as an Application Engineer. So he still has contacts with Sencore people.He is hard to get in contact with as he travels for a new company. But he still list's his many Sencore items for sale. He is only home once a week and shipment times can take a while.I just received it and started to check it out. As noted .. The LC102 Does show Ua and a good bad indication. But no impedance as the LC103.What's got me is the unit posted is for sale on another site and has pictures of each button press under test. As you can see.. That one shows "0" Ua.

author: Bill Kelso
author_rank: Newbie
timestamp: December 04, 2023, 04:50:11 pm
content: Quote from: coromonadalix on December 04, 2023, 11:29:18 ambut i think the 103 gives an impedance measurement scale / vs leakage, but reading the user manual will tell you moreyou could ask : volvo_nut_v70 in the sell thread second pagehe as one to sell right now, he could do some "compare"Thanks coromonadalix for the reply. I really appreciate it.I have read the manual.. And it does talk about leakage and refers you to the leakage chart. But the unit never shows leakage, just Impedance with "0" Ua. Also I am totally familiar with the Don't touch the leads when the LED is flashing..L.O.L. I used to have an LC103 when working as a repair tech for the Golden Nugget Casino in Atlantic City repairing all there Pro Sound gear. Any way I have had the LC102 which I picked up about 2 months ago. This deal with the LC103 came up and I knew I had to repair something.But what's got me confused is that I have seen one on Youtube that does show Leakage and Impendence in the Leakage test ....and the one for sale on another site in this picture I posted that doesn't. I can't remember when I used mine back in the day in my shop if it showed Ua or not.I would hate to find out that it's an big IC that is messed up. I do have a Pace de-soldering station. But that is something I don't want to have to do if it is and IC... Maybe a Relay with Dirty contacts that feeds info to the display from an IC. Whish full thinking....L.O.L.

author: alm
author_rank: Super Contributor
timestamp: December 04, 2023, 05:56:29 pm
content: Quote from: Bill Kelso on December 04, 2023, 04:50:11 pmI haven't used the LC-103, but I would expect it to work the same as the LC-102, and also inthis videoit shows both current and resistance. Unless the cap really has less leakage than the LC-103 can measure like a fancy polystyrene cap. What happens if you connect a resistor that at the voltage should result in a current that's in range? If it keeps showing 0 uA, then my guess is that there's a defect in the current sensing circuit or even in the voltage source (try measuring the voltage it puts out, being of course careful of the high voltage).Quote from: Bill Kelso on December 04, 2023, 04:34:57 pmI hope that's not Lance from Choice Electronics. His reputation in theSencore Owners groupis not exactly stellar. Just search there for his name or his company name.

author: Bill Kelso
author_rank: Newbie
timestamp: December 04, 2023, 10:07:59 pm
content: Quote from: alm on December 04, 2023, 05:56:29 pmQuote

author: alm
author_rank: Super Contributor
timestamp: December 04, 2023, 10:15:22 pm
content: Please fix your way of quoting, it's very hard to read this way. Type afterCode:Have you measured the output voltage? Because if its outputting 0V, then the current will also be 0 uA

author: Bill Kelso
author_rank: Newbie
timestamp: December 04, 2023, 11:18:16 pm
content: Quote from: alm on December 04, 2023, 10:15:22 pmSorry about the quote thing. I Thought it was beginningQuoteI have always done that. Any way to answer your question Yes... Set for 500 Volts and my test meter reads 495 Volts. Thanks for the question and help. The only thing I can see mechanically is the relay contacts being dirty. But those plastic cases are hard to remove in circuit to clean the contacts.

author: coromonadalix
author_rank: Super Contributor
timestamp: December 05, 2023, 12:09:38 am
content: be carefull you have a calibration sheet, there s a small offset on the output voltage vs the real onei had an lc102 i put the schematics and stuff there with others, you have stuff for 102 and 103http://www.ko4bb.comhttp://www.ko4bb.com/manuals/74.57.239.193/Sencore_LC102_Calibration_Procedures.pdfthere is a sheet from the 102 who tells the voltages you should get .... 1kv i think gave 997v as per calibration .... some 4-5 volt difference and was per Sencore specsthe 102 had the big relay oxidation in it, pierce a small hole with a twist drill and shoot some deoxit, it resolved the issue, do not use sand paper, and let all of it dryin some cases one of the small relay too, mine had bettter ones, but i cleaned the big relay.I would use this sheet to do some check but not touch anything inside the 103sadly we never got all the stuff for an 103, there was some calibration sw never posted as promised etc ...

author: Bill Kelso
author_rank: Newbie
timestamp: December 06, 2023, 12:57:32 am
content: Quote from: coromonadalix on December 05, 2023, 12:09:38 amThanks: The LC102 is fine. And I did some research on Youtube. This guy knows the inside of the LC 103 unit and must be an "EE" and have computer based background. He was showing and talking about the inside and pulled the E Prom Out and Copied it as he said they have Life span of about 30 Years. So he copied it using his equipment and then was running thru the code showing all the commands Etc.Basically he said that the unit is programed with special Sencore gear that is no more when it was made at the Factory. So to your point the only option I have is to Mess with the relays and some D-5. Other then that it does not look like I can repair it. Volvo Nut sent me the skids. So I have that. I'll pop your links open and check them out after I finish this post.Thank you for taking the time to research the items. I really do appreciate it.Regards:Edit::Also your link ends up in the same place but does not show any Sencore gear.. I'm sorry...maybe I' missing something. Any way Check out this guy and you'll see how complicated the LC103 is. Way be yond my pay grade as far as programing and understanding some of what he is doing.enjoy.