Hacking the Victor VC-921

[itsthatidotagain]

If anybody has a bit of spare time and wants to hack another DT0660 based meter, they might like to take a look at the

http://www.ebay.co.uk/itm/302325367550?_trksid=p2055119.m1438.l2649&var=601161562576&ssPageName=STRK%3AMEBIDX%3AIT
http://www.ebay.co.uk/sch/i.html?_from=R40&_sacat=0&_nkw=zt+102+multi+meter&_sop=15


AN8002 also known as the ZT102 and the RM102 and others.



This is actually quite a good value and reasonably robust meter.

It differs from the VC912 in that the pads for the COB are not all broken out, so the pins for the IR serial port may not be available.

[TheRadioGeek]

Hello all,

I am new to all this software EEPROM stuff and have some questions. I have a VC-921 pocket meter that I would like to change the EEPROM to allow it to be 8000 count and maybe change the auto power off time. I have a Minipro TL866 universal programmer and was able to read the eeprom and get the following. I however don't know what to change to get the above unlocked. Could someone tell me what I need to change and how do you find out what to change and what to change it to when doing something like this.

Thanks

FF FF FF FF FF FF FF FF FF 52 00 FA 00 00 BE 03
A0 0F 68 10 7C 01 6E 50 64 4B 3C 3C 0A FF 40 FF
80 98 F1 81 64 00 96 00 00 80 00 80 00 80 00 80
4E 02 09 58 05 09 1D 04 0B B9 11 0A 7B FF 09 00
00 01 00 01 00 07 98 00 64 00 64 00 64 00 00 00
00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80
7D 7F 00 83 01 00 81 2A 00 00 00 00 00 00 00 00
08 81 00 80 8A 82 E0 7C 18 01 00 00 00 00 00 00
00 00 00 06 00 00 00 05 00 07 00 0A 12 09 0B 0E
00 00 00 00 00 00 00 0D 00 02 11 0F 00 00 00 15
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
0D 00 02 10 0D 00 03 20 20 00 03 20 20 00 03 10
41 00 03 08 41 00 03 05 41 00 03 05 0D 00 02 20
00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80
3C 7F FF FF FF FF FF FF 5A C7 CC 0F 0F 80 00 00

[Rbastler]

In the datasheet of the chipset is everything you need.
You just need to open a .bin file and change it and reflash the eeprom with the changed .bin file. I cant think of other solutions with a TL866.
It got a VC921 too, and this is where I'm stuck atm....

Sent from my A0001 using Tapatalk

[TheRadioGeek]

Hey guys and gals,

I got my vc 921 to be a 6000 count meter thanks to the data sheet from http://www.kerrywong.com/2016/04/03/dtm0660-datasheet-translated/ . It's for the dtm0660 chip that this meter has under that blob.  I did try to change the auto off time but it gave me an error when I tried to program  the EEPROM.  I took a screen shot of the programming changes. changes are in RED. The one red one at the bottom was me trying to change the auto off time. It has the default of 0f.

thanks Rbastler

[Rbastler]

How did you manage to make the changes in the eeprom ? I cant figure out how. Is it possible right with the tl866 ?

Sent from my A0001 using Tapatalk

[TheRadioGeek]

You will need a SOIC 8 dip to clip cable. see photo. You hook up the cable to the ZIF socket on the programmer and clip the other end on the legs of the EEPROM on the PCB. Make sure pin 1 is lined up with pin 1 on the cable. Red stripe is pin 1 on the cable. On the programmer pick Atmel 2402 and hit the read button. Save what you read  from the chip to a bin file just in case you mess things up and need to load it back into the chip. Make your changes by clicking on the address you want to change and typing in the values you want. Now push the program button and you should be all set.  I got my cable on Amazon for about $10 but I'm sure you can find it on Ebay too. Try a search for SOIC 8 clip programming cable.

Hope that helps.
Good luck.

 

[Rbastler]

You will need a SOIC 8 dip to clip cable. see photo. You hook up the cable to the ZIF socket on the programmer and clip the other end on the legs of the EEPROM on the PCB. Make sure pin 1 is lined up with pin 1 on the cable. Red stripe is pin 1 on the cable. On the programmer pick Atmel 2402 and hit the read button. Save what you read  from the chip to a bin file just in case you mess things up and need to load it back into the chip. Make your changes by clicking on the address you want to change and typing in the values you want. Now push the program button and you should be all set.  I got my cable on Amazon for about $10 but I'm sure you can find it on Ebay too. Try a search for SOIC 8 clip programming cable.

Hope that helps.
Good luck.

Yes, that did help ! 
Didn't knew you could modifie EEPROM content in the MiniPro software.
I bought a Soic adapter cable, when I bought the VC921 on Aliexpress, so no problems there.

[Rbastler]

Here my successful attempt at modifying the EEPROM for more counts plus a comparison to my Fluke 8050A measuring a quick and dirty AD584 reference:

[TheRadioGeek]

Nice photos of the modified meter in action. I am glad you got it all working. I got mine set to 8000 count as well. I made a how to video if anyone wants to see how its done. DO THIS AT YOUR RISK.



Its kind of neat that you can change this stuff!!  Fun fun 

[necromncr]

Just wanted to add - Zotek ZT102 has a button placeholder on the back of the PCB called RANGE. It actually works and switches AUTO to MANUAL range mode!

[sarel.wagner]

This time a really really simple hack. The lead storage for Lab use is silly, so I cut a piece out of the case for the leads. Now I can close the lid without worrying about trying to store the leads.

Youtube short video here https://youtu.be/pQweOiUN2hI

[SandPox]

Hey, I just found that you can enter calibration mode on VC921 by holding REL and RANGE button while it's turned on, switch off and then switch on the meter, it will beep few times while display all the character on the screen then it will enter "CAL" mode with some weird looking character, I worry that I might mess up the calibration of my meter so I switched it off immediately, it still seems fine though

[Fungus]

Hey, I just found that you can enter calibration mode on VC921 by holding REL and RANGE button while it's turned on, switch off and then switch on the meter, it will beep few times while display all the character on the screen then it will enter "CAL" mode with some weird looking character, I worry that I might mess up the calibration of my meter so I switched it off immediately, it still seems fine though

Didn't work on mine... 

[Rbastler]

Hey, I just found that you can enter calibration mode on VC921 by holding REL and RANGE button while it's turned on, switch off and then switch on the meter, it will beep few times while display all the character on the screen then it will enter "CAL" mode with some weird looking character, I worry that I might mess up the calibration of my meter so I switched it off immediately, it still seems fine though

Not on mine.... Afaik you need to short two pads in order to get into cal mode.

[SandPox]

Somehow I was not able to enter it anymore, the screen blinking with all character and beeping but it never ends.. huh, strange!

edit: sometimes I power it up while holding two button and it only display APO REL but the number doesn't show up, maybe it enter some kind of secret mode?

[dacson]

I ordered a Victor VC921 recently (24.05.2018), after i only found offers for the Zotek VC921/Aneng 8203 for a while, which is based on a different chipset/design afaik. I was a little bit afraid that the seller didn't know the difference and that i might instead receive a Zotek/Aneng "clone". To my surprise, i really received a Victor VC921, with the tall numbers on the display and the oval buttons.

But what's really interesting is that it came with the DM1106EN as QFP instead of as COB, just like in my UT210E. Not sure if this changes anything in regard to hackability as all pins seem to be in use anyway, so i guess a COB would have had all pads bonded as well. Still, i prefer this over a COB with (maybe) unbonded pads under the black gunk.

What i don't like is the bend PTC with its bare feet coming quite close to the (i guess) clamping transistors. Solved that with some kapton tape until i have access to my iron again.

Edit: Actually, on a second glance, four pins seem to be unused and could potentially be unbonded on a COB. And sorry that this is more of a teardown post, i have a second unit in the mail that i will hack, once i have access to my tools again, and report here.

[shved]

So, I've needed cheap platform for logging with some degree of safety for some time. After searching, I've found this and similar threads and ordered Victor VC921. Couple days ago the box arrived and I got to work.

Chinese seller sent me different rev. The knob and buttons are a different color, PCB rev. is different too.
EEPROM editing is simple.
Chip is not COB on my rev. it is in TQFP as per datasheet! UART TX pin is small and fiddely to solder a wire to, huge pain in the ass!
To insure some safety I've made IR interface as in datasheet example schematics. But added ring - magnet connection like Apple mag-safe. The IR LED and IR photo-transistor can be salvaged from decommissioned electricity meters/counters(same duty there).
Also I've added input banana sockets and deleted original probes.

Anyway, after I finish the tests, wait for glue and make some stickers - I can take some pictures

[bffargo]

Thanks everyone for this hack and links and descriptions. I successfully changed my ~7 year old one to 8000 count.

I was unable to change any byte past $0080 (like in the Select multi function table). The programmer would write the earlier changes to the count area ($0010) but would get a verify error on the random things I tried above $0080.

Anyone else experience this? Any ideas why?


On a tangent, I tried to read the 24C02 on my ANENG 8008 and it failed to read at all giving an error during read. Do I need to remove the XTAL or short across it or is it something else?  I don't think there are any hacks for it (only the earlier 8002) but wanted to read out the eprom now since I was working with testers.

[shved]

Photos of my dataloging setup, as promised.

[shved]

more photos