Tektronix 1485R - UK Vintage Radio Repair and Restoration Discussion Forum

electroanorak · 10th Aug 2007, 1:56 pm

Hello all,

I have a Tektronics 1485R waveform monitor, that has a slight fault in that the +5 volt supply for the logic has dropped to 3.6 volts and the trace has gone dim

.

Rite !!! The +5 volt rail is derived from a centre taped winding on the EHT transformer, this would explain the 2 faults.

If I disconnect the the supply to the logic and use a seperate supply for it, all is ok (screen just dim), so it is not the logic dragging it down.

I have been through all the other obvious causes.... and there is nothing in the EHT side that is causing a problem.

I have started to trace the schematic from the PCB, but I have not got the peace and quiet and time at the moment...

If anyone has a service manual for one of these, I would be so greatfull if you could e-mail me just the schematic for the PSU

... I have contacted Tek, and they told me that support for this ended in 2000

and £35.00 + P&P for the manual is a bit naughty.

Thank you in advance...

Daniel.

ppppenguin · 10th Aug 2007, 2:42 pm

I used to have one of these and a manual. I'm pretty sure I sold it (complete with manual) to a forum member but I can't remember who. Maybe this will jog some memories.

jim_beacon · 10th Aug 2007, 7:20 pm

I have the 1485 and manual from Jeffrey. The manual is about 150 pages of data and diagrams. I'll try and scan it, but it will take some time, even with the new auto feed scanners at work. I'll post it on my website when it is done.

£35 for the manual is probably reasonable at current copying and labour costs!

Jim.

electroanorak · 10th Aug 2007, 8:14 pm

Thank you.. but please dont go to all the trouble to scan the whole manual, as I know how time consuming it can be.
Just the PSU bit will do for now, and when you get time to do the rest, I would rather send you some payment for doing it. and for your kind offer of help wtrh this..

Thank you....

Daniel.

jim_beacon · 10th Aug 2007, 10:19 pm

Dabiel,

I have to unbind (spiral bound, so it's not a problem) the manual to scan it, so, apart from the diagrams, it will go through the auto-feeder. I'll try and make a start on Monday - PSU bits first.

The manual isn't on-line, so I need to do it all at some point (along with about 20 other Tek manuals....).

Jim.

jim_beacon · 25th Aug 2007, 9:38 am

Daniel,

the first 200 and something pages of the manual are now here:

www.g1jbg.co.uk/service.htm

near the bottom of the page. I'll try and do the diagrams this week, however, they are a bit time consuming, as each foldout page needs four scans, they are roughly 1.5 times the size of an ordinary A3 page, and double sided, and there are around 20 of them!

Sorry it's taken so long to get this far.

Jim.

electroanorak · 25th Aug 2007, 11:16 am

Thank you for that.
Please don't rush....
I am in the middle of my clear-out anf will let you know what I find...

Daniel.

ppppenguin · 25th Aug 2007, 11:29 am

I remember that manual. It's big and chunky. I'd call it a heroic effort scanning that lot, especially the big fold out circuits. Presumably you scan them in sections and stitch them together somehow.

jim_beacon · 25th Aug 2007, 1:43 pm

Luckily, the drawing is usually A3, and the notes and waveforms roughly A4, so it lends itself to a two part scan. If a diagram goes over two parts, I'm more likely to leave it as two pages, trying to stitch them together electronically often leads to problems, it is usually better to print, then use the traditional cut and paste method.

The standard pages aren't too bad, as we (work) have a scanner which will handle double sided and A3 on auto-feed, but you still need to limit the input to about 30 pages at a time, and the Tektronix spiral binding holes often lead to paper jams (the trick is to scan the pages "back-to-front", and then rotate them in Acrobat), there are a number of blank pages to edit out as well.

I'll try and get the 520 and 521 Vectorscope manuals, and the 529(including the mod 188) Waveform monitor manuals scanned whilst I'm at it, though I think that may take a long time. There are also a lot of 500 series scope and plug-in manuals here, though most of those are available via BAMA.

Jim.

10th Aug 2007, 1:56 pm	#1
electroanorak Hexode Join Date: Apr 2007 Location: Tonyrefail, Rhondda, South Wales, UK. Posts: 337	Tektronix 1485R Hello all, I have a Tektronics 1485R waveform monitor, that has a slight fault in that the +5 volt supply for the logic has dropped to 3.6 volts and the trace has gone dim. Rite !!! The +5 volt rail is derived from a centre taped winding on the EHT transformer, this would explain the 2 faults. If I disconnect the the supply to the logic and use a seperate supply for it, all is ok (screen just dim), so it is not the logic dragging it down. I have been through all the other obvious causes.... and there is nothing in the EHT side that is causing a problem. I have started to trace the schematic from the PCB, but I have not got the peace and quiet and time at the moment... If anyone has a service manual for one of these, I would be so greatfull if you could e-mail me just the schematic for the PSU... I have contacted Tek, and they told me that support for this ended in 2000 and £35.00 + P&P for the manual is a bit naughty. Thank you in advance... Daniel.

10th Aug 2007, 2:42 pm	#2
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Tektronix 1485R I used to have one of these and a manual. I'm pretty sure I sold it (complete with manual) to a forum member but I can't remember who. Maybe this will jog some memories.

10th Aug 2007, 7:20 pm	#3
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Tektronix 1485R I have the 1485 and manual from Jeffrey. The manual is about 150 pages of data and diagrams. I'll try and scan it, but it will take some time, even with the new auto feed scanners at work. I'll post it on my website when it is done. £35 for the manual is probably reasonable at current copying and labour costs! Jim.

10th Aug 2007, 8:14 pm	#4
electroanorak Hexode Join Date: Apr 2007 Location: Tonyrefail, Rhondda, South Wales, UK. Posts: 337	Re: Tektronix 1485R Thank you.. but please dont go to all the trouble to scan the whole manual, as I know how time consuming it can be. Just the PSU bit will do for now, and when you get time to do the rest, I would rather send you some payment for doing it. and for your kind offer of help wtrh this.. Thank you.... Daniel.

10th Aug 2007, 10:19 pm	#5
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Tektronix 1485R Dabiel, I have to unbind (spiral bound, so it's not a problem) the manual to scan it, so, apart from the diagrams, it will go through the auto-feeder. I'll try and make a start on Monday - PSU bits first. The manual isn't on-line, so I need to do it all at some point (along with about 20 other Tek manuals....). Jim.

25th Aug 2007, 9:38 am	#6
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Tektronix 1485R Daniel, the first 200 and something pages of the manual are now here: www.g1jbg.co.uk/service.htm near the bottom of the page. I'll try and do the diagrams this week, however, they are a bit time consuming, as each foldout page needs four scans, they are roughly 1.5 times the size of an ordinary A3 page, and double sided, and there are around 20 of them! Sorry it's taken so long to get this far. Jim.

25th Aug 2007, 11:16 am	#7
electroanorak Hexode Join Date: Apr 2007 Location: Tonyrefail, Rhondda, South Wales, UK. Posts: 337	Re: Tektronix 1485R Thank you for that. Please don't rush.... I am in the middle of my clear-out anf will let you know what I find... Daniel.

25th Aug 2007, 11:29 am	#8
ppppenguin Retired Dormant Member Join Date: Dec 2003 Location: North London, UK. Posts: 6,168	Re: Tektronix 1485R I remember that manual. It's big and chunky. I'd call it a heroic effort scanning that lot, especially the big fold out circuits. Presumably you scan them in sections and stitch them together somehow.

25th Aug 2007, 1:43 pm	#9
jim_beacon Retired Dormant Member Join Date: Mar 2003 Location: Bishop's Waltham, Hants, UK. Posts: 939	Re: Tektronix 1485R Luckily, the drawing is usually A3, and the notes and waveforms roughly A4, so it lends itself to a two part scan. If a diagram goes over two parts, I'm more likely to leave it as two pages, trying to stitch them together electronically often leads to problems, it is usually better to print, then use the traditional cut and paste method. The standard pages aren't too bad, as we (work) have a scanner which will handle double sided and A3 on auto-feed, but you still need to limit the input to about 30 pages at a time, and the Tektronix spiral binding holes often lead to paper jams (the trick is to scan the pages "back-to-front", and then rotate them in Acrobat), there are a number of blank pages to edit out as well. I'll try and get the 520 and 521 Vectorscope manuals, and the 529(including the mod 188) Waveform monitor manuals scanned whilst I'm at it, though I think that may take a long time. There are also a lot of 500 series scope and plug-in manuals here, though most of those are available via BAMA. Jim.