component tester

This was a very useful gadget, but when I last switched it on the screen is displaying gibberish. I've tried a new battery, and leaving it without a battery for a bit. Before I dump it and buy another anyone got any idea how to get it back in order

No idea what it is or what components you wish to test, but does it require an internal cell to retain memory (CR2032 cells are common)?

Could it be the connection between the display and the PCB? It looks as if there are some rows/columns missing. Probably not worth spending a lot of time on considering how much they cost. Be aware that although they all appear to look the same the fixing holes in the PCB vary from make to make. I bought a board a while back and recently found case at low cost but had to modify it to fit my board. Interesting that it uses the same processor as the Arduino Uno and Nano.

Peter

Duncan,

I was installing a robot many moons ago on an Injection moulder and when I powered it up I accidently pressed the language button which immediately turned everything on the screen to japanese, I only had an english manual and had to contact my japanese collegues to tell me how to get it back to english. The R in the round makes me think its a register mark refering to the square of characters on its left, do you have multi lingual instructions that you can look at to see if there is some way of getting it back to english.

Martin P

Two possibles, change the battery, or do a 'hard reset'. This usually involves pressing a specified key and holding it down as you switch the device on, or poking a pin through a small hole somewhere, which does the same thing, ie restores the factory settings. You may have to look hard in Google to find the details.

Could be a firmware fault ,it seems to be based on atmega 328 ,firmware files on internet.You could try reflashing it.

I think you need to give more details than just "A component tester" For example model number, manufacturer, the magazine article you built it from. I think it is expecting a lot for it to be recognised from just a picture of the display.

Les.

Edited By Les Jones 1 on 08/06/2020 08:47:59

Wrong attitude Les. on a recent "Over the pond" forum it took four pages and sixty odd replies to get the relevant information, reply 65 solved the problem.

Much more exciting having to "Ass u me"

Regards Ian.

+1.

I think this is the same unit.

I believe the display is a press fit to a zebra connector on the board; ie a connective pad, no wires or soldered joints. On mine the display's plastic locating pin top right just above the printed '15' has been glued, but the other - diagonally opposite, is free.

The top of the display has a bit of black tape that may be holding it together!

Although they work remarkably well in practice, zebra connectors needs a certain amount of pressure to work. I wonder if they might misbehave if knocked sideways, or be vulnerable to condensation? Maybe not - playing with an old digital caliper, I found the display remarkably robust and unfussy.

Try pressing the display on to the board gently, or releasing the mounting screws. (Duncan's unit misbehaves after being put in a proper box, whilst my neglected bare board still works! Maybe Duncan's display has been upset by the way the board is mounted in the box?)

Dave

PS I only know they're called Zebra Connectors thanks to this forum!

It's displaying some of the display correctly, so the problem is not necessarily with the display.

The mix of incorrectly displayed characters and characters from the wrong place in the character set suggest it may be a memory fault.

Neil

Try pressing the display on to the board gently, or releasing the mounting screws. (Duncan's unit misbehaves after being put in a proper box, whilst my neglected bare board still works! Maybe Duncan's display has been upset by the way the board is mounted in the box?

Dave This is really interesting because the display on my unit changed when I put it in a case. It now has a background of many dots. Not enough to make it unusable, just annoying.

Peter

Duncan, look at:

https://www.eevblog.com/forum/testgear/$20-lcr-esr-transistor-checker-project/msg659867/#msg659867

you need reply 939, by Tom 666 (in bold atop the relevant posting)

Thanks for the replies. It is exactly as SOD shows. I've tried pressing the display down, even lifted it up slightly from the board and pressed down on the connector underneath with a spatula, all to no avail. The idea of re-flashing the memory is above my pay grade I fear, so it's hand in pocket time. Never mind, with lockdown we're hardly spending anything. Don't let SWMBO read this, she'll take it as a challenge. If anyone wants the defunct one it's yours for the postage, but probably not worth it, a new one is <£10

Duncan

Geoff, thanks for the link. I now know that I have an LCR-T3 board and a case for an LCR-T4.

Peter

FWIW, it looks like this is what Duncan's screen is trying to say [sixth image down]:

https://ameblo.jp/millimeter-wave/image-12308987583-14023174928.html

The two Chinese characters read Haoqi.

Edited By Bill Phinn on 09/06/2020 00:30:54

Is it a metal case? That two units misbehave when cased by their owners might be more than a coincidence! LCD displays are enormously common - billions of them - but they're almost always enclosed in plastic.

I'm inclined to think its a mechanical problem. If I'd boxed mine up, I'd have done it exactly as Duncan has with mounting bolts through the front panel. But front-mounting might stress the connection between LCD and board when the bolts are tightened perhaps sliding it sideways over time? Possibly safer to mount the board on pillars from the other side leaving the LCD panel completely unstressed.

Re-flashing is an interesting idea. The bottom of the tester's board has a rectangle of six unused holes next to the crystal that might be an ISCP header. (I haven't checked the CPU pins it goes to.) This Instructable explains how to flash an Arduino Nano from a Uno via ISCP, so should be possible. But because this is a commercial product, Duncan doesn't have a copy of the image. I believe it's possible to extract a hex dump of a loaded program with avrdude, but I've never tried it. Maybe I could copy the program image from my working unit, send it to Duncan, sort out the detail of loading from HEX vs BINARY, and then follow the instructable. Could be a lot of work for no return if the display connector is damaged, particularly as these testers are so cheap.

Bit like when a neighbour asks for a complicated part for his mower to be made. Replicated in Bronze after a few hours on lathe and mill plus much head-scratching and CAD planning. Then he mentions you've saved him £1.99!

Dave

I suggest you post a request for assistance on Vintage Radio, I do know several members have bought similar devices as I have. They are very good, but I'm unable to be of assistance.John

I've ordered a new one, not worth messing with re-programming even if I thought I could do it. I'll mount the new one differently, just need to stop the battery hanging off the wires and eventually falling off

Circles is the ISP header for the AVR. Identify which are the VDD and GND connections ( and 5V) and you can orient the connector.

Reflashing could be a fair bit of faff as you need a suitable programmer and software.

Personally I wouldln't bother as they are so cheap...

Just a thought.. does it still misbehave out of metal box?

Just to say the LCD is "powered" via what was described by sticky tape.

Also contacts are present on topside of the pcb so might

be shorted by case .

It might be stuffed but it might not .

Btw I think it might be working but in " foreign"