Find great deals for Datron DIGIT Selfcal Digital Multimeter – Faulty. Shop with confidence on eBay!. Wavetek/Datron Multi-Product Calibrator .. The from Wavetek/Datron is a high performance, 8½ digit bench top multimeter. It can measure direct voltage. Datron repair. «on: January 26, , am». Hey. «Last Edit: February 02, , am by whatamidoing». Logged.
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Common rival for these system multimeters is well known HP A and Keithley This article will cover two different unit, with second generation Wavetek-branded logo, produced somewhen in Detailed specifications are presented later in manuals section of this article.
Datron also have self-cal technology, with is targeted to compete with Autocal feature of HP A. There are no official man manufacturer service for this old DMM s anymore, so hopefully we will not need custom unobtainable components, as that can easily put repair into BER. But if we get units in question repaired, we will be doing calibration in-house, using calibrated HP A and Fluke B DC voltage standard.
As usual, all photos are clickable for high-resolution version. Redistribution and use of this article or any images or files referenced in it, in source and binary forms, with or without modification, are permitted provided that the following conditions are met:. All information posted here is hosted just for education purposes and provided AS IS. In no event shall the author, xDevs.
Datron – DMM Meters
If you willing to contribute or add your experience regarding test instruments repairs or provide extra information, you can do so following these simple instructions. Datron Users manual, Issue 6, Feb Datron Calibration and service manual, Volume 1 and 2, Issue 1, July Datron Calibration and service manual with schematics, Volume 2, Issue 2, January Datron Calibration and service manual with schematics, Volume 2.
Credits for storing these manuals goes to KO4BB. Datron Service manual, Calibration and servicing. Itron does not have any stock for the display and do not have public documentation for it.
But thankfully, we got and able to share full datasheet for DCE2. Testing VFD display output and test connections. Datron and lesser brother using interesting arrangement for primary power supply with two big toroidal transformers. First transformer converts mains to low voltage supply for earth-referenced digital domain, and powers low-voltage PWM DC-DC around second transformer, with switching frequency in sync with mains.
Secondary outputs of this low voltage transformer are rectified and regulated with usual LDO s to provide clean analog supply voltages. What is the benefit in such double conversion? We already know, that temperature changes are our main enemy in high precision voltage and current measurements, so Datron had to make extra effort to reduce instability of temperature contributors, instead of adding fans or heat sinks around critical components.
Datron and are the using unusual arrangmenet for main voltage reference. Model using two identical Linear LTZ based modules, labeled Datronwith custom hermetically sealed Vishay metal foil resistor network, while Model using LTZ module and LM module to save cost. In out units refereces were enclosed in black epoxy, and would be troublesome to remove from PCB for teardown. Unit was received as advertised.
Datron DIGIT Selfcal Digital Multimeter – Faulty | eBay
Meter was failing with error message — C03 immediately after power on. While testing optocouplers with second Datronit was noticed that error codes were different on second meter if optocouplers were left out of circuit. Possibly one of the daughterboards was failing? A quick check of all cables to the main DC board showed one that was not connected and stuffed under the main board. Not good, as this shows someone was diagnosing an issue that required the board to be possibly removed from the frame.
After reconnection cable, this error code went away and first DCV readings were acquired. It looked good with the input shorted, however the OHM s readings were open. Another search for connector issues showed the input connector was hastily plugged in and had missed a pin on the DC board, pushing it aside.
A quick reconnection and all the ranges appeared to respond as expected with the short on the input. A screw was also missing that held the dahron in place. The errors are broken down based on the type of test.
The Fast test failure code is explained in section 2. It tests the mean value with the inputs shorted on the mV range. Good rule of thumb is dahron replace all batteries if instrument is older than 10 years. Without further diagnosing of the error, the inguard and outguard supplies needed to be tested as the parts have datecodes from and the lithium backup battery is dated from Its voltage was measured at 3.
The schematics for both the inguard and outguard supplies were scanned. Test points for the DC board were easily found as Datron did not use silkscreening on their boards and used unmasked copper for the TP numbers on the DC board. The Digital board, however, has no markings and does not match the component layout drawing in the service manual.
Neither boards have any REV markings on the top, but might be located on darron bottom side. Another datrom of board is shown below:.
Digital board, courtesy of www. Re-seating all chips would be a good idea, considering age of the instrument and unknown history. But first 2181 first, power supply checks. The outguard supplies located on this PCBA were measured once suitable test points were found:.
The firmware version appears to be 3. The board plugs into a single socket and has an additional wire connecting to it marked A17 most likely for datrkn additional address line to other memory ROM s.
The digital board is removed by taking out screws from the rear cover. The power supply and ribbon cables also need to darton disconnected. The board and rear cover come out as one assembly. All seven capacitors were changed with only one gotcha. The lithium battery was replaced with a TLP. Replacement of battery was performed with unit powered on and a battery powered soldering iron was used to avoid loosing calibration constants and SRAM daatron. After disconnecting lots of cables and wires, main DC board was released and removed.
Might be worthy to take a note of cable locations before removing PCBA:. This colorful PCBA have all critical components for DC and main voltage reference modules, covered by black plastic covers.
DATRON 1281 8.5 DIGIT Selfcal Digital Multimeter
2181 We will look into those later on, after repair. Capacitors which should be replaced are marked on schematics in blue. All but two capacitors were replaced on the DC board 12 of A couple of gotchas were found during the change out. It appears the mounting holes were too close together and did not match capacitor pin spacing.
Another gotcha is that it is important 181 note which lead is offset as there are some components that darton prevent it from going in properly. Two of the capacitors actually would touch each other and this is solved with the offset leads. At least one positive lead is soldered to the pcb in through a pad but it is not usually shaped for the polarity square-vs-round.
The other leads are soldered straight to components with insulating sleeves. Two of these capacitors were relatively easy to remove by clipping them at the mating lead. The old lead was left on the part and the new lead was soldered next to it. There was concern daatron additional heat could have caused issues with the aging parts. The other two capacitors were surrounded by other parts preventing them from being changed easily. It was decided to continue troubleshooting at this moment and replacing them would have been done later.
All tests completed now without errors. No issues datrno noted with the AC assy. That likely caused some excessive currents flow thru webs and poor bug, causing measurement issues. No issues were noted with the Ohms assy. It was bought by Vishay in early During reassembly of the bottom half of the meter, it was discovered datrom the Current assembly had some difficulty with the three connectors at the front of the pcb.
Looking at the wires an interesting issue was found. It appears that the two outside connectors were placed in the opposite location. The satron are a little short and there is some noticeable stress. The power was left on and a battery powered soldering iron was used.
The power input filter was also replaced as a precaution. The ground cable is exposed so additional heat shrink was added to the P and N terminals. The power supplies were remeasured.
All supplies are close to as-found except the V supply. It was now measuring This second unit actually happens to be the the first Datron acquired. It was chosen to repair last repair due to the number of errors. Repair procedure is very similar to previous box. This unit comes with Options 10, 20, 30 and 70, so it have full set of boards and modules to play with.
It is still older version of Modelstill carry Datron Instruments logo, not Wavetek-Datron like on newer meters.