Datron 1065A service manual - Page 1
Forum section: electronics / repair

author: torquil
author_rank: Regular Contributor
timestamp: August 05, 2021, 05:30:52 pm
content: I bought a Datron 1065A and it seemed to work the first few minutes. However, then I heard a sort of ticking noise, similar to the noise you hear when a heater is turned off and it is cooling down fast. After that the meter was always showing "over limit" no matter what I did on any range, and errors 5, 6 and 7 on the self test. I was lucky to get the service and calibration manual for 1065/1065A with the meter.It turns out the tantalum capacitor C14 near the integration circuit was toast, along with a nearby resistor that is connected between the capacitor and ground. It was easy to find the error after checking the test points oscilloscope waveforms shown near the integration circuit. I changed it to a multilayer ceramic of the same value, and now it works again.But my real question is: I did not find the 1065A service manual online. Should I scan mine and upload it, or is it already available somewhere, despite my failed attempt to find it online?Best regards,Torquil

author: Gyro
author_rank: Super Contributor
timestamp: August 05, 2021, 06:50:16 pm
content: You can find it on KO4BB...http://www.ko4bb.com/getsimple/index.php?id=manuals&dir=06_Misc_Test_Equipment/DatronEDIT: Ah, sorry, I'd forgotten that was the datasheet only. It would certainly be worth scanning and uploading - KO4BB and BAMA being the best places.EDIT1: The 1061 isveryclosely related, and is available for download - you might be able to save effort by just scanning the specific differences.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 05, 2021, 10:56:32 pm
content: I have done a few videos fixing the 1062, it may be of help.My suggestions are to replace all electrolytics, the power supply ones are probably still ok but do them anyway. The ones on the analogue board WILL be bad, they always are.Replace the two round bridge rectifiers, they seem a common failure too, I put in W02 instead of the original W01.There are tantalum caps on the power supply board, upgrade them all, replace the 25v with 35v snd the 6.3v with 10v, this is needed due to the original under rating for the supply rails they are on, always try to at least double the V rating vs supply V for tants.

author: torquil
author_rank: Regular Contributor
timestamp: August 06, 2021, 11:34:42 pm
content: Quote from: TheDefpom on August 05, 2021, 10:56:32 pmThanks, I will follow those suggestions. I have watched many of your videos, and also the Datron ones, they are very helpful (and entertaining).Now I have to find out the correct battery size designation, because apparently I had assumed that it was the same type of battery as in my HP 3478A, which it unfortunately is not. It has a smaller diameter.I think I will scan the service manual some time and upload it.

author: TheDefpom
author_rank: Frequent Contributor
timestamp: August 06, 2021, 11:48:05 pm
content: The battery is a 1/2 AA 3.7V

author: torquil
author_rank: Regular Contributor
timestamp: August 07, 2021, 04:53:42 pm
content: Quote from: TheDefpom on August 06, 2021, 11:48:05 pmThanks! And I just found that the C10 or C11 tantalum cap in the power supply was completely burned up.... They were 22 uF 25 V. Didn't have any 22 uF 35 V tantalums, so I took the chance on changing them both to some new Nichison aluminium electrolytics at 25 uF 25 V. While I was at it I changed the input IEC filtered power input to a brand new one, just to be sure.

author: torquil
author_rank: Regular Contributor
timestamp: August 27, 2021, 11:45:27 pm
content: Quote from: TheDefpom on August 05, 2021, 10:56:32 pmI replaced them, and they were bad. Especially the 10 uF ones. ESR was around 150 Ohm.