Solartron-Schlumberger A100 Oscilloscope.
Ian Field
The scope looks to be in reasonable condition, sometimes the trace appears
for a few seconds - it has once or twice stayed a little longer.
If anyone knows where I could download the schematic - that would definitely
come in handy!
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Lewin A.R.W. Edwards (Despammed)
> Does anyone know what the most common causes of no trace on the screen?
Faced with a very similar problem and no documentation, my first reaction
was to open up and look at all the test points I could find on the board. If
your unit has TP voltages labeled on the PCBs then checking these is a great
place to start.
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-- Lewin A.R.W. Edwards
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Ian Field
"Lewin A.R.W. Edwards (Despammed)" <sp...@larwe.com> wrote in message
news:_U1n8.1836$n8....@nwrddc02.gnilink.net...
Actually, it's been a while since I opened it up and had a look - I couldn't
figure it out so I decided to put it back together and leave it alone before
I messed it up worse! But I don't remember seeing any test points - or if
there were any, they didn't have any screen-print legend to indicate their
purpose. This seems to be a fairly good spec scope - but very definitely
"built to a price"! But if I can get it going - it would be huge loads
better than the "old banger" I dragged out of a skip nearly 20 years ago. A
while back the CRT emission got so bad I had to replace all the diodes in
the anode multiplier with TV efficiency diodes, to boost the EHT - the rise
in beam current finished off what vestiges of calibration were left! I'd be
quite happy if I could get my old Solartron CD1400 going again - but I think
that's given up smoking for the last time! (high-voltage transformer = stock
fault!).
Geo
>Actually, it's been a while since I opened it up and had a look - I couldn't
>figure it out so I decided to put it back together and leave it alone before
>I messed it up worse! But I don't remember seeing any test points - or if
>there were any, they didn't have any screen-print legend to indicate their
>purpose. This seems to be a fairly good spec scope - but very definitely
>"built to a price"! But if I can get it going - it would be huge loads
>better than the "old banger" I dragged out of a skip nearly 20 years ago. A
>while back the CRT emission got so bad I had to replace all the diodes in
>the anode multiplier with TV efficiency diodes, to boost the EHT - the rise
>in beam current finished off what vestiges of calibration were left! I'd be
>quite happy if I could get my old Solartron CD1400 going again - but I think
>that's given up smoking for the last time! (high-voltage transformer = stock
>fault!).
If I remember right, a "stock fault" on A100 was failure in the (potted) eht
system (at the rear - long white box) - so suspect the handbook may not help. I
doubt if I still have a handbook for one since have had 2 moves - each time to
smaller premises and unused stuff got "put out" each time :-(
I still use a CD1400 at work for the odd job (yes, had to replace a transformer
on that too).
Geo
Sam Goldwasser
> Does anyone know what the most common causes of no trace on the screen?
>
> The scope looks to be in reasonable condition, sometimes the trace appears
> for a few seconds - it has once or twice stayed a little longer.
>
> If anyone knows where I could download the schematic - that would definitely
> come in handy!
Any time something happens erratically, look for bad connections. On a
scope that sees/has seen little use, connectors tend to oxidize so reseat
everything in sight.
The location could really be anywhere in the power supply, HV, or grid
baising circuitry.
--- sam | Sci.Electronics.Repair FAQ Home Page: http://www.repairfaq.org/
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Ian Field
"Geo" <gm4xus@yahoo.c?.uk> wrote in message
news:gepp9useroooo2r93...@4ax.com...
Thanks for the info - what's inside the long white box? If It's not too
complicated, I could probably improvise with salvaged EHT components from a
TV or monitor.
Since I actually have the CD1400 manual (as far as I can remember from the
last time I looked - contains the schematics), something I'd had the idea
of - but probably won't ever get round to doing! was to build an SMPS unit
to replace the transformer, I'm sure I remember looking up what all the
voltages are, and deciding that the flyback panel from a mono monitor - or
more likely a Wyse "thin client" terminal would handle the only output too
high for conventional SMPS modules.
Ian Field
"Sam Goldwasser" <s...@saul.cis.upenn.edu> wrote in message
news:6wlmcjd...@saul.cis.upenn.edu...
There's a strong suspicion that the scope had been left stored in a factory
unit that gets cold & damp overnight - so as I'm not so familiar with
oscilloscope construction, I'd more or less confined my "tinkering" to
checking out this very possibility. It's been stored in less hostile
conditions now I have it - but I fear messing it up completely if I wade in
without at least some of the proper service info!
Geo
>Thanks for the info - what's inside the long white box? If It's not too
>complicated, I could probably improvise with salvaged EHT components from a
>TV or monitor.
OOps - I mis-remembered slightly - the long box was the CD16xx which was
battery/mains - the later CD1740 similar problems. Anyway the A100 /metal/ cover
shields the EHT section which consists of 2 pcbs (4 and 5).
The EHT is +8.5kV (tripler from transformer) with a tap for -1.5Kv (to crt
cathode) and a separate winding for -1.6kV (for grid bright-up). The osc circuit
is a couple of BFY50's running at 20kHz.The -1.5kV is fed back through a string
of 3M resistors to the primary voltage regulator circuit for the oscillator.
I found my handbook - but it's my old workshop copy - much scribbled on and
tattered. The most thumbed page (hint) is the CRT and bright-up circuit (pcb 2)
which drives the grid. RV5 is the pre-set brilliance control. It is in a string
of resistors which should be R51 and R52 8.2M and R53 12M. TR22 (MM1614 pnp)
used to give trouble.
I'll see if I can scan the eht and bright-up circuits and put a .tif file on my
web page.(Monday)
>Since I actually have the CD1400 manual (as far as I can remember from the
>last time I looked - contains the schematics), something I'd had the idea
>of - but probably won't ever get round to doing! was to build an SMPS unit
>to replace the transformer, I'm sure I remember looking up what all the
>voltages are, and deciding that the flyback panel from a mono monitor - or
>more likely a Wyse "thin client" terminal would handle the only output too
>high for conventional SMPS modules.
The CD1400 had a 3Kv mains-derived EHT which was quite painful if you were not
expecting to touch it. The string of 8uF/450v multiplier caps on the bottom
board caused lots of faults but the hi-voltage winding was also a problem.
Are you in UK?
Geo
Ian Field
"Geo" <gm4xus@yahoo.c?.uk> wrote in message
Many thanks for that, it does sound like a "probable cause" that I can
check. If you can find time to scan the schematics that would be very handy.
Not sure what this NG is like, but I upset a load of people last time I
uploaded attach to a non-binaries group! my request is also posted on
alt.binaries.schematics.electronic - it's perfectly OK to upload there. Your
scanner's probably better than mine - my old heap produces TIFF file of at
least 1Mb regardless of image content! Either way, you can probably get at
least some reduction using Irfanview to convert to GIF, with the TIFF files
from my scanner - the GIF files come out from 40kb to about 300kb depending
on image content. Irfanview is excellent freeware, and it's well known - so
easy to find the download site with any good search engine.
Geo
>Not sure what this NG is like, but I upset a load of people last time I
>uploaded attach to a non-binaries group! my request is also posted on
>alt.binaries.schematics.electronic - it's perfectly OK to upload there. Your
>scanner's probably better than mine - my old heap produces TIFF file of at
>least 1Mb regardless of image content! Either way, you can probably get at
>least some reduction using Irfanview to convert to GIF, with the TIFF files
>from my scanner - the GIF files come out from 40kb to about 300kb depending
>on image content. Irfanview is excellent freeware, and it's well known - so
>easy to find the download site with any good search engine.
2 a3 sheets split into 4 x A4 then scanned at 300 dpi.
Used PSP to save as compressed tif - about 100k each - converting to gif changed
size very little.
available from:-
http://www.lintech.pwp.blueyonder.co.uk/a100.zip
Geo
Ian Field
"Geo" <gm4xus@yahoo.c?.uk> wrote in message
Thanks, very grateful for that.
If there's anything you need in the way of datasheets or TV/monitor
schematics - I have something of a collection. Much of it still needs
sorting into folders so I know where to find it, but there's always that
possibility that I might just happen to have that hard to get chip
datasheet. (there's also a few telephone schematics - they're all in
Russian, so the only chance of getting the one for my phone was to download
the lot & see if any matched on chip manifest!).
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