Soviet F4103 earth ground tester teardown.  - Page 1
Forum section: electronics / testgear

author: ResR
author_rank: Regular Contributor
timestamp: July 02, 2015, 03:14:19 pm
content: Serial number 04283, not very much mass produced item.The top cover was missing when I found it.The analog meter has serial number 88881 hand written onto the dial plate.Takes 9 1,5V D cells or 12V through custom made socket, that has extra 2 pins to isolate batteries when cap is removed.Oldest surface mount chips I have seen. These chips are 134TV1, K134AB1 (chip made in 1984) and K134TV14 in an odd metal cap case, looks like military grade parts.Everything has been lacquer covered, built to last for decades. It has 3 transformers inside.Engineered to be serviceable. These switches does feel very reliable and has good mechanical response.Chips are KR143KT1, UD70V and K284UD1V in a case that looks like a crystal oscillator case.I like the attention to detail, capacitors bodged at the other side of the board has plastic sleeves on and hand written the markings onto the sleeve. The M6 bolt, plastic bobbin and nut combination is my repair to reattach the carry strip at one end.Planning to get it working and use it when the company I'm working for is going to bankrupt and I'm on my own.

author: Illukas
author_rank: Newbie
timestamp: July 02, 2015, 04:52:29 pm
content: "Planning to get it working"Start by replacing all the capacitors. The axials have all popped - note the bulging foam cap on one end.

author: ResR
author_rank: Regular Contributor
timestamp: July 02, 2015, 05:08:42 pm
content: That's a good idea and taken into plan.

author: free_electron
author_rank: Super Contributor
timestamp: July 02, 2015, 05:12:56 pm
content: It's amzing 4283 were made. Nkrmally you only would have needed one, state owned, and, in true communism fashion, shared between all inhabitants equally. ....

author: poorchava
author_rank: Super Contributor
timestamp: July 02, 2015, 05:32:56 pm
content: Probably this is what happens when the state has to create many unneeded jobs because every adult citizen is legally obligated to work.Sent from my HTC One M8s using Tapatalk

author: ResR
author_rank: Regular Contributor
timestamp: August 02, 2015, 05:07:32 pm
content: Recapped. I had mixture of Panasonic, Rubycon from old power supply and Leaguer (?) 105C capacitors. Now I need new batteries to test it and figure out what these cyrillic letters means.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 03, 2015, 05:46:42 am
content: Quote from: free_electron on July 02, 2015, 05:12:56 pmEven in Oz,back in the day,such devices weren't common items in anybody's tool box,unless they were involved with such testing every day.My Employer had a unit for testing equipment power leads & extension cords,etc.which lived in a big Road case.It was rotated through all the sites throughout the year.On one occasion,we found the readings a bit suspect,in that it "OK'd" a known faulty cord.We noticed that the tester rattled,so "popped it open".A couple of big electros had come adrift---on resoldering them,it worked correctly.I often wonder how many faulty cords had been "given a clean bill of health" before it came to us!No doubt there will be expressions of horror that we dared to open it,but "then was then",& "if it was on the site,& it was faulty,you fixed it!" was the philosophy.This applied to non-Electronic stuff like Diesels,too----if it was within our abilities we fixed it!

author: Balaur
author_rank: Unknown
timestamp: August 03, 2015, 01:59:18 pm
content: Quote from: Illukas on July 02, 2015, 04:52:29 pmWhere?They look quite OK for me. Or at least, on par with all the russian capacitors that I've seen in my youth.The lacquer doesn't seem to be broken.

author: vk6zgo
author_rank: Super Contributor
timestamp: August 03, 2015, 10:49:49 pm
content: Quote from: Balaur on August 03, 2015, 01:59:18 pmIf you are used to British "metalmite" type capacitors,the Russian ones look faulty,but are just a different package.I have seen ones with similar packaging in some older German equipment,which are equally deceptive.

author: ResR
author_rank: Regular Contributor
timestamp: August 07, 2015, 07:22:51 pm
content: I totally forgot I have adjustable power supply (cheap garbage with the TO-3 transistor (writings are worn off) as a regulating component, but works for me).I put 12V in from battery terminals using home made crocodiles (towel loops), all test terminals open to see it operate and the needle went only to 6 on only one "PTN" setting. On other settings it has no operation, range setting doesn't change anything also. Also "IZM" button doesn't do anything. Any ideas how to test it properly (resistors?) or is it broken?

author: Bud
author_rank: Super Contributor
timestamp: August 07, 2015, 08:42:13 pm
content: They say T1 and T2 are the current source terminals (~300hz @36V with the open circuit) , so you can check if it generates that voltage across the terminals.The other two terminals are the internal voltmeter input. So you inject current from T1 T2 and measure voltage drop using those voltmeter terminals.Battery check procedure:Short all terminals togetherSet switches to PTN and 0.3Push ISM buttonThe movement should go to the black sector - means battery check passedCalibration procedure:Set the mode switch to KLBAdjust YST0 pot to zeroize the meterPush ISM button and adjust KLB pot to set the movement to 30How to use and the above stuff is here:http://diplomka.net/publ/izmerenie_soprotivlenija_zazemljajushhikh_ustrojstv/6-1-0-368

author: mazurov
author_rank: Frequent Contributor
timestamp: August 07, 2015, 09:07:35 pm
content: Just FYI, "?" on the gauge means "limit".

author: unitedatoms
author_rank: Frequent Contributor
timestamp: August 08, 2015, 02:13:21 am
content: Letter ? stands for P-potentialLetter K stands for C-currentOrange transistors are either KT315 npn or KT361 pnp depending on location of letter like KT315? will be marked just ?. The letter is located on left for KT315 or in the middle for KT361. They can be replaced by any jelly bean low power silicon trcansistors.Black TO-126 transistor is KT814,KT815,KT816 or KT817. Medium power silicon.Diode bridge?? ??906 may beThe transformer coils data and tech support and contact information is here: Ukraine.You can try call them and ask for technical support.http://izmer-ls.ru/ost/f4103-3.htmlQuoteThe military grade chips did not have K at the beginning. Usually military SMT were pink saphire body with gold plated cap and a lot more writings printed on chip.Schematics is may be this F4103-M1, not sure if M1 makes a differencehttp://www.enes26.ru/forum/attachment.php?attachmentid=379&d=1352981001

author: ResR
author_rank: Regular Contributor
timestamp: August 08, 2015, 06:22:35 pm
content: It didn't operate as instructed, the needle moved without the IZM button to around 6 on PTN and 0,3 and KLB was too erratic to make sense - first it showed nothing, then after sitting on 12V for a minute when I rechecked the procedure the needle climbed to 8 and didn't move with or without pressing IZM button. I took it apart again and found a zener diode "V18" with white and red band with wider gap between the two lines that looks like burnt from white band (chip) side. The voltage output at T1 and T2 was 3,6-6,8V AC, unstable.Looks like it's has been sitting on the shelf for too long.Quote from: unitedatoms on August 08, 2015, 02:13:21 amThanks for help but it looks a little bit different schematic, mine doesn't have LED's in or on it.Edit: The diode looks like one inhttp://savepic.su/2766104m.jpgfirst from right.

author: Bud
author_rank: Super Contributor
timestamp: August 08, 2015, 10:31:04 pm
content: The zenner seems to be a KC168A 6.8V part, the voltage reference in the 10V power supply. If it is bad, the power supply would not work properly, so you may need to start from probing the power supply +10V output as per the schematic. I'd think the schematic would be much relevant, the "M" index typically stands for "modified" , so the base schematic should be very much the same. Component designators may differ though, which seems to be the case here - it appears the power supply component designators in the schematic are 2x (i.e. V25-V28) and on your board they are 1x (V15-V18). Try measuring the voltage across the zenner (expected +6.8V) and collector of KT814 (expected +10V).

author: ResR
author_rank: Regular Contributor
timestamp: August 09, 2015, 07:24:17 am
content: Voltage across zener* is 0,3V and across C-E of KT814 is 0,68V - all three pins had positive or negative 0,68V reference to the zener ground rail with 12V input across the battery terminals. Something started to whistle for a moment when I raised the input voltage from 0 to 5V.Now it climbs to 8 on PTN and throws the needle to other end with any other setting without pushing any buttons. I didn't keep it powered any longer after finding that.*I made a crude one from 10 1n4148s in series as the original was open circuit and checked it drop voltage using series 2,2k resistor and power supply and measured the voltage across the diodes to be 6,6V with 12V and spot on 6,8V with 20V input.Edit: Found a real 6,8V zener from salvaged board but the result is the same.