Dartron D20 Dual Trace Scope - Page 1
Forum section: electronics / repair

author: Prime
author_rank: Regular Contributor
timestamp: June 24, 2016, 10:17:18 pm
content: Hi there,I have a Dartron D20 Dual Trace scope that I'd like to fix. Does anyone have a copy of the manual lying around or know where I can find one?One channel works, the other is dicey - i just can't remember what is wrong with it since it's been a while.Thanks

author: tautech
author_rank: Super Contributor
timestamp: June 24, 2016, 10:28:32 pm
content: You'll need to get it out and recheck things but for now just try and give the faulty channel selectors some "exercise" in case there's just some oxidisation on the selector/switch contacts.Can you post up a pic of the display showing the fault?There's quite a bit you can do without a manual as you've got one working channel to get measurements from.If you have another scope you can just follow the input signal path (both channels same signal, internal 1KHz Cal is good)) until you find where it goes astray. Then check the components in that stage.

author: tautech
author_rank: Super Contributor
timestamp: June 24, 2016, 10:35:51 pm
content: Google can't even find any Darton scopes, you'd better post a pic of the scope just in case we recognise it as a rebrand.Pretty obscure brand, all I could find:http://www.collection.archivist.info/searchv13.php?searchstr=Dartron+ISSeems like you have to contact then for the manual to be scanned.

author: Hydrawerk
author_rank: Super Contributor
timestamp: June 24, 2016, 11:01:46 pm
content: Datron or Darton?

author: tautech
author_rank: Super Contributor
timestamp: June 24, 2016, 11:32:56 pm
content: Following a few leadsI wonder if it's the same as this one:http://www.radiomuseum.org/r/grundig_oscilloscope_mo_20mo2.html

author: Prime
author_rank: Regular Contributor
timestamp: June 25, 2016, 02:26:57 pm
content: Quote from: tautech on June 24, 2016, 11:32:56 pmDartron. See I made a typo in the post (not the title)

author: Prime
author_rank: Regular Contributor
timestamp: June 25, 2016, 02:48:09 pm
content: Quote from: tautech on June 24, 2016, 11:32:56 pmNope.Pictures attached. I opened it up last night to look inside but forgot to take pictures. It's all discrete components on two large boards (No valves like my philips) and Nichicon capacitors. The tube said made in Kent so I assume it's British made but there is no address on the labels on it.Quote from: tautech on June 24, 2016, 10:35:51 pmYeah, that is all I have turned up. I'll probably email him next week if I don't come rightQuote from: tautech on June 24, 2016, 10:28:32 pmThe second channel doesn't detect anything and it's very noisy.I'll put it on a signal gen at work and see if I can trace the location of the fault. Good Idea. ThanksAlso, I see the tube needs a slight rotation

author: coppice
author_rank: Super Contributor
timestamp: June 25, 2016, 03:42:54 pm
content: The kinda looks like a Scopex scope with a replacement front sheet that says Dartron. E.g.http://www.radiomuseum.org/r/scopex_oscilloscope_4d10a.html. Obviously not that exact model, as the buttons are different, but it looks similar enough that I would guess there is common ancestry/

author: Prime
author_rank: Regular Contributor
timestamp: June 29, 2016, 11:03:07 pm
content: Quote from: coppice on June 25, 2016, 03:42:54 pmThe inside is completely different. The knobs are fairly complex and couldn't be split like that. And this scope uses at least 3 pcbs.I presume that stub is some sort of impedance match.So I found the first problem - broken wire from the input conditioner circuits on the control knob. But it looks like I will need to replace those matched input jfets that are in sockets. I blew one swapping them out to test channel 2. It's reading but it's under reading now.ITT and Nippon? capacitors.Sent from my HTC One_M8 using Tapatalk