Thorn AVO B184 LCR meter - Page 1
Forum section: electronics / general

author: Janne
author_rank: Contributor
timestamp: October 04, 2011, 07:08:29 pm
content: Hi,I have an older LCR analyzer from Thorn, that recently gave up the ghost. Rechargeable internal batteries shorted after only 24 years of use. It's not too high spec(on todays scale anyway), max. measuring freguency is 1kHz but it's still plenty good for my uses. I've lost the manual for the unit, is it possible the batteries could be any other chemistry than NiCd? The cells are 2/3A size, so at least they're easily still available. Also, if someone has a manual for this thing, either a .pdf version or a paper copy I would be interested.Attached are some pictures of the device and the cells, un-soldered from the board. The text on the cells reads VARTA D6.The device itself is quite what you would expect. The main processor on the device is HD63701, a single chip computer from hitachi. It runs at a whopping 500kHz clock, from the 2MHz xtal. Looks like it must have been really cutting edge back thenBuild quality is excellent, with all through-hole components, except of course the driver IC's on the HD44780 LCD display. Interesting detail to note about the crystal is that they've actually gone and soldered a ground lead to the case. Only thing that feels a bit dodgy is the piezo wires, which have been directly soldered to the board, being the only thing that prevents completely separating the board from the cover. The soft buttons have a nice stiff feel to them and are still working without problems. It used to have a decent battery life of several hours, but before completely dying the usable time without charger was down to about 5 minutes.The 12-bit A/D converter has a whopping 0.03ksps sample rateAnd of course parallel interface.

author: amspire
author_rank: Super Contributor
timestamp: October 04, 2011, 11:36:15 pm
content: I think NiMH only became commercially available about 1989, so the batteries are almost certainly Nickel Cadmium cells.The fact they shorted sounds exactly like NiCD.So i would guess something like Ebay # 370419468548. Tabs don't quite fit, but you can make them fit. Probably more capacity then the original Varta's.Richard.

author: Janne
author_rank: Contributor
timestamp: October 05, 2011, 12:05:53 am
content: Thanks for the reply. Those ebay cells look they will fit nicely with a bit of cutting and bending on the tabs.

author: IanB
author_rank: Super Contributor
timestamp: October 05, 2011, 01:02:23 am
content: Here's another battery option:http://www.batteryjunction.com/nc-2-3a-700hd-t.html

author: Bored@Work
author_rank: Super Contributor
timestamp: October 05, 2011, 06:35:53 am
content: Quote from: Janne on October 04, 2011, 07:08:29 pmVarta still exists. Although they are right in the middle of being split into various parts and disinvestment ... If you hurry you might still reach one there who can identify the batteries, either at what are now called Varta Microbattery or Varta Consumer.

author: Janne
author_rank: Contributor
timestamp: October 05, 2011, 10:06:36 am
content: Quote from: BoredAtWork on October 05, 2011, 06:35:53 amI dropped them an e-mail and they pretty much confirmed they're NiCd. Good customer service from their part!