UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Vintage Test Gear and Workshop Equipment

Notices

Vintage Test Gear and Workshop Equipment For discussions about vintage test gear and workshop equipment such as coil winders.

Closed Thread
 
Thread Tools
Old 8th Jun 2018, 3:50 pm   #1
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,190
Default AIM/Racal LCR Databridges

This follows on from a thread in the 'stuff wanted' section, concerning making an adapter for the Racal Databridge.

Some years ago I was given one of these instruments, non-working and with no accessories. Mine is badged 'AIM Databridge' and doesn't have the IEEE488 interface (it's described as an option in the manual) but is clearly much the same instrument.

The real reason it didn't work was poor conenctions at the EPROM sockets inside (the unit is controlled by a Z80 microprocessor) which were easily cured by replacing the sockets with turned-pin types. Alas The Phantom / M0RON had got there first and replaced 74C906 and 74C907 ICs (logic level shifters) with 74C90 counters (!). Getting replacements for those was interesting (and annoying as I'll wager the originals were not defective, they just didn't test as 74C90 counters!), I think I had to make a bodge up for one of them. It now works fine apart from one missing display segment (I forget if it's the display or the driver IC that's failed, but the instrument is useable without it).

One thing I did get with mine was the circuit diagram. This does not seem to be available on-line anywhere (I am sure it is not 'up top', so I don't think I am breaking any rules by saying this). It's a fairly poor copy, but a lot better than nothing. If anyone wants it I will be happy to get it to them.

I'd be interested in hearing how others get on with making up the adapters, as I might have a go myself... The user manual I have does mention using a scrap of double-sided copper-clad board in the right-hand component connector to connect to an external PSU to apply a bias voltage (up to 50V) to a capacitor under test.
TonyDuell is offline  
Old 8th Jun 2018, 6:56 pm   #2
PETERg0rsq
Heptode
 
PETERg0rsq's Avatar
 
Join Date: Jun 2009
Location: St Helens, Lancashire, UK.
Posts: 641
Default Re: AIM/Racal LCR Databridges

Tony

I have two Racal Databridges, one with a full set of accessories if you need any pictures or other information.

I also have a full service manual for the Racal 9341, which the schematics are from AIM, but no designation as to which AIM model.

I have the user manual for the 9343M

If any of these are of use to you let me know and I will scan them for you.
__________________
SPECIALIST.....Knows everything about nothing
EXPERT..........Knows nothing about everything
PETERg0rsq is offline  
Old 8th Jun 2018, 7:06 pm   #3
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,190
Default Re: AIM/Racal LCR Databridges

I am pretty sure the AIM and Racal units are much the same internally, I think they carried other manufacturer's names too. I am not sure what the different models are, though.

I found the Racal 9343 user manual on-line, but not the service manual. Does the latter contain any useful information other than the schematics (which I have)? I have some basic troubleshooting information in the AIM user manual, but it's really just checking power supplies and clocks, and a few analogue signals.
TonyDuell is offline  
Old 8th Jun 2018, 7:18 pm   #4
Diabolical Artificer
Dekatron
 
Diabolical Artificer's Avatar
 
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,637
Default Re: AIM/Racal LCR Databridges

Can you test power transformers and chokes with these bridges? I have a Marconi TF2700 but without the power tfmr test jig, so testing these is pretty much impossible. They look like good bridges.

Andy.
__________________
Curiosity hasn't killed this cat...so far.
Diabolical Artificer is offline  
Old 8th Jun 2018, 7:31 pm   #5
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,190
Default Re: AIM/Racal LCR Databridges

Strictly it's not a bridge, at least not electrically. It measures the in-phase and quadrature components of the connected impedance (at either 100Hz or 1kHz) and calculates the resistance and capacitance/inductance from that. But it does the same job as a traditional AC bridge, so I guess the name stuck.

It'll measure inductance up to some quite high value. But it will not measure mutual inductance (maybe needed for some transformer tests) and it will not measure inductance (AFAIK) with some DC current flowing to check the core material performance.

What does the power transformer testing jig do for your Marconi instrument?
TonyDuell is offline  
Old 9th Jun 2018, 9:36 am   #6
radioman
Heptode
 
radioman's Avatar
 
Join Date: Apr 2003
Location: Ayr, Ayrshire, UK.
Posts: 630
Default Re: AIM/Racal LCR Databridges

I have one of these - it's an AIM LCR Databridge 401 and I would be very interested to get a copy of any user manuals/circuit diagrams.

Andy
radioman is offline  
Old 9th Jun 2018, 11:14 am   #7
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 22,800
Default Re: AIM/Racal LCR Databridges

Thanks for the diagram, Tony. There really doesn't seem to be one anywhere else.

David
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now  
Old 9th Jun 2018, 12:31 pm   #8
PETERg0rsq
Heptode
 
PETERg0rsq's Avatar
 
Join Date: Jun 2009
Location: St Helens, Lancashire, UK.
Posts: 641
Default Re: AIM/Racal LCR Databridges

Quote:
Originally Posted by TonyDuell View Post

I found the Racal 9343 user manual on-line, but not the service manual. Does the latter contain any useful information other than the schematics (which I have)? I have some basic troubleshooting information in the AIM user manual, but it's really just checking power supplies and clocks, and a few analogue signals.
I only have copies of the 9341 maintenance manuals (2 x pdf and one paper).

Circuit descriptions, calibrations, fault-finding tree, parts list, schematics. Same as any other Racal maintenance manual.

What schematic drawing numbers do you have?

I do not have any schematics for the 9343 in my collection.

Just for information, I collect Racal manuals, then scan and upload to KO4BB

I keep a list of Racal manuals I own on the Racal_Dana user group on Yahoo and on my website http://www.g0rsq.co.uk/manuals.htm (along with many other manuals) if anyone is looking for something particular that is not already on KO4BB.
__________________
SPECIALIST.....Knows everything about nothing
EXPERT..........Knows nothing about everything
PETERg0rsq is offline  
Old 9th Jun 2018, 1:24 pm   #9
radioman
Heptode
 
radioman's Avatar
 
Join Date: Apr 2003
Location: Ayr, Ayrshire, UK.
Posts: 630
Default Re: AIM/Racal LCR Databridges

Thanks for that information - I managed to download the service manual from KO4BB for the Racal-Dana 9341 which, from the information in it, looks to be the same as the Aim 401 I've got.

Andy
radioman is offline  
Old 9th Jun 2018, 1:42 pm   #10
TonyDuell
Dekatron
 
Join Date: Jun 2015
Location: Biggin Hill, London, UK.
Posts: 5,190
Default Re: AIM/Racal LCR Databridges

Thanks, I've downloaded the service manual too. It's almost identical to the manual that came with my AIM databridge.
TonyDuell is offline  
Old 10th Jun 2018, 1:15 pm   #11
Diabolical Artificer
Dekatron
 
Diabolical Artificer's Avatar
 
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 7,637
Default Re: AIM/Racal LCR Databridges

Quote:
Originally Posted by TonyDuell View Post
What does the power transformer testing jig do for your Marconi instrument?
It allows you to measure an inductor with DC bias. I've started a new thread here - https://www.vintage-radio.net/forum/...77#post1050677

Andy.
__________________
Curiosity hasn't killed this cat...so far.
Diabolical Artificer is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 10:49 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.