I have no affiliation with the seller.
-Kurt
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Hi
I got this scope used and when i started it i couldnt get a trace, after some fiddling i discovered that the trace was as wide as the screen.
There is some reaction from the controls and i can move the light on and off screen.
I repair and build tube amps so i have some basic electronic skill.
Anyone had this problem or similar please help.
Thanks in advance/Roger
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Re: OT: Question about LM334 and 1N457
David,
In theory that may be so, but try telling *all* my 7071 and 7081 meters that this is the case - the AC buffer amplifier drifts for a lengthy period after power on. Before the latest change (C714 replacement) this has typically been over 24 hours before it stabilised. I'm still waiting to see how much better this might be after replacing C714. First signs are encouraging, but I've been misled before.
Regards,
David Partridge
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-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of David
Sent: 14 July 2012 21:05
To: TekScopes@...
Subject: Re: [TekScopes] OT: Question about LM334 and 1N457
Every time I read the LM334 data sheet, I wonder the same thing. The
1N457 is not particularly fast or low leakage so I do not know what distinguishes it for this application other than the data sheet recommendation and comment about temperature coefficient which is not all that helpful in finding a replacement without testing.
The LM334 data sheet and application notes have enough information to calculate the required temperature coefficient. I would just build a circuit and fixture to test a variety of diodes including common transistor junctions.
The temperature coefficient of the current source for the 7081 AC Buffer should not affect the output anyway. If it does, then something else is wrong.
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Re: OT: Question about LM334 and 1N457
Every time I read the LM334 data sheet, I wonder the same thing. The 1N457 is not particularly fast or low leakage so I do not know what distinguishes it for this application other than the data sheet recommendation and comment about temperature coefficient which is not all that helpful in finding a replacement without testing. The LM334 data sheet and application notes have enough information to calculate the required temperature coefficient. I would just build a circuit and fixture to test a variety of diodes including common transistor junctions. The temperature coefficient of the current source for the 7081 AC Buffer should not affect the output anyway. If it does, then something else is wrong. On Sat, 14 Jul 2012 19:18:04 +0100, "David C. Partridge" <david.partridge@...> wrote: The LM334 datasheet specifies the use of a diode to cancel the temperature coefficient of the LM334, saying:
"The recommended diode for use in this circuit is the 1N457 because its tempco is centered at 11 times the tempco of the LM134, allowing R2 = 10 R1."
All well and good, but the 1N457 datasheet doesn't specify the TC, and anyway the 1N457 is getting rather hard to find.
Can anyone recommend a suitable substitute? Ideally in a surface mount package.
Thanks
David Partridge
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Re: OT: Question about LM334 and 1N457
Perhaps better for David, Farnell have them as well.? Since they are made by Fairchild, they should be using the correct ex-National process.
I don't know a surface mount equivalent.
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On Sat, Jul 14, 2012 at 12:47 PM, Leon Robinson <leon-robinson@...> wrote:
David,
Mouser has buckets of 1N457's at $0.14 each.
Leon Robinson ?? K5JLR
Political Correctness is a Political Disease.
--- On Sat, 7/14/12, David C. Partridge <david.partridge@...> wrote:
From: David C. Partridge <david.partridge@...>
Subject: [TekScopes] OT: Question about LM334 and 1N457
To: TekScopes@..., hp_agilent_equipment@...
Date: Saturday, July 14, 2012, 1:18 PM
?
The LM334 datasheet specifies the use of a diode to cancel the temperature coefficient of the LM334, saying:
"The recommended diode for use in this circuit is the 1N457 because its tempco is centered at 11 times the tempco of the LM134, allowing R2 = 10 R1."
All well and good, but the 1N457 datasheet doesn't specify the TC, and anyway the 1N457 is getting rather hard to find.
Can anyone recommend a suitable substitute? Ideally in a surface mount package.
Thanks
David Partridge
|
|
Re: OT: Question about LM334 and 1N457
David,
Mouser has buckets of 1N457's at $0.14 each.
Leon Robinson ?? K5JLR
Political Correctness is a Political Disease.
|
--- On Sat, 7/14/12, David C. Partridge wrote:
From: David C. Partridge
Subject: [TekScopes] OT: Question about LM334 and 1N457
To: TekScopes@..., hp_agilent_equipment@...
Date: Saturday, July 14, 2012, 1:18 PM
?
The LM334 datasheet specifies the use of a diode to cancel the temperature coefficient of the LM334, saying:
"The recommended diode for use in this circuit is the 1N457 because its tempco is centered at 11 times the tempco of the LM134, allowing R2 = 10 R1."
All well and good, but the 1N457 datasheet doesn't specify the TC, and anyway the 1N457 is getting rather hard to find.
Can anyone recommend a suitable substitute? Ideally in a surface mount package.
Thanks
David Partridge
|
Re: Polish out scratches in blue filter
Good Day,
based on experience with CRT-filters in my 5000 series and a 7704A I can recommend some milder car polish.
The product I use is named SONAX NANO car polish, which is intended for new cars and I use great care when applying it.
Hint: What I have found out myself is that the follwing works well:
I use a common sanding block, which I clean very thoroughly. Then, I use a clean cotton cloth and wet it. I wrap it carefully and tightly around the sanding block and use a small amount of the car polish at a time. I mark the worst scratches with some car polish first and make only circular moves.
The sanding block allows me to apply pressure much more evenly than when doing it by hand. And the handling becomes very ergonomical, too.
I excessively clean the CRT filter between using plain soap and water.
Then, I re-inspect the surface and continue with those spots which need another round of polishing; until all areas are shiny again.
For the final clean, I use some distilled water and cotton cloths to dry.
Cheers,
Magnus
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I have no affiliation with the seller.
-Kurt
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OT: Question about LM334 and 1N457
The LM334 datasheet specifies the use of a diode to cancel the temperature coefficient of the LM334, saying:
"The recommended diode for use in this circuit is the 1N457 because its tempco is centered at 11 times the tempco of the LM134, allowing R2 = 10 R1."
All well and good, but the 1N457 datasheet doesn't specify the TC, and anyway the 1N457 is getting rather hard to find.
Can anyone recommend a suitable substitute? Ideally in a surface mount package.
Thanks
David Partridge
|
Re: Polish out scratches in blue filter
I have had excellent success polishing the Tektronix CRT filters using a graded series of polishing products manufactured by Novus Incorporated in Minneapolis, Minnesota. I buy them from either a local retail plastic supply house or from McMaster-Carr Supply Company. It is very easy to buy from McMaster-Carr and they ship incredibly quickly. Specifically, the three products I use are: Novus 3 Heavy Scratch Remover Novus 2 Fine Scratch Remover Novus 1 Plastic Clean & Shine Novus 3 and Novus 2 are graded abrasive polishing compounds in thin paste form. Novus 1 has no abrasive and is used for final cleaning and adds a shine. Severe damage cannot be removed with these polishing compounds. But, taking 600 grit emery paper to a CRT filter will seriously scratch the surface so I would not do so over a wide area. Finer grit papers are certainly available from industrial hardware stores; I have papers down to 6000 equivalent grit. The old-time crocus cloth is still available! Auto supply stores sell kits for polishing discolored plastic head light lenses. I find these kits a bit over-priced but they are readily available. Also readily available is a product called, SimiChrome Polish by Happich. It is sold for polishing metal and should be tested first for compatibility before using on plastics. But, on any metal, it is really good. I have used the Novus products for many years and I do recommend them. Larry On 7/14/2012 7:55 AM, Steve Vineyard wrote: I found a product call Flitz that says it is for Metal, Plastic,
fiberglass and restores paint. It works well for me on everything I
have tried it on. Got it originally to polish out an acrylic watch
crystal. Worked very well for that and aluminum. Very mild fine
polish. Takes a little time due to being so fine. Due to being so fine
it will not take out deep scratches. Would need to sand with 600 or
finer sand paper first. I found it in a local knife shop or you can go
to www.flitz.com. ... -- Best wishes, Larry McDavid W6FUB Anaheim, California (SE of Los Angeles, near Disneyland)
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Re: Polish out scratches in blue filter
I found a product call Flitz that says it is for Metal, Plastic, fiberglass and restores paint. It works well for me on everything I have tried it on. Got it originally to polish out an acrylic watch crystal. Worked very well for that and aluminum. Very mild fine polish. Takes a little time due to being so fine. Due to being so fine it will not take out deep scratches. Would need to sand with 600 or finer sand paper first. I found it in a local knife shop or you can go to www.flitz.com.
Steve, KJ5RV
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Re: [TekScopes2] OT: Solartron 7071 for auction on UK eBay
Yes, eBay cancelled the listing because I said I preferred purchasers not to use Paypal.
I relisted it.
Regards,
David Partridge
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-----Original Message----- From: TekScopes@... [mailto:TekScopes@...] On Behalf Of geoffrey thomas Sent: 14 July 2012 15:03 To: TekScopes2@... Cc: TekScopes@... Subject: [TekScopes] Re: [TekScopes2] OT: Solartron 7071 for auction on UK eBay This listing (280921474992) has been removed, or this item is not available. ? Geoff. On 14/07/2012 14:24, David C. Partridge wrote: I've just put a Solartron 7071 up for auction on UK eBay:
<>
Cheers
David Partridge ------------------------------------ Yahoo! Groups Links
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Re: [TekScopes2] OT: Solartron 7071 for auction on UK eBay
This listing (280921474992) has been removed, or this item is not available.
?
Geoff.
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On 14/07/2012 14:24, David C. Partridge wrote: I've just put a Solartron 7071 up for auction on UK eBay:
<>
Cheers
David Partridge
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Re: OT: Solartron 7071 for auction on UK eBay
Now it is under: <>
Regards,
David Partridge
|
Ah, looks like the djvu has what I need. I assumed they were the same. Silly me.
Thanks!
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--- In TekScopes@..., "nerritv" <neveenstra@...> wrote:
Hi,
I recently picked up a few nonfunctional 465b's as a pet project and the one in question is of e low serial number variety. Anyway, I'm looking for a complete set of the troubleshooting flowcharts. The flowcharts in the manual on bama for the 465b are incomplete scans and the portion in specific that I'm looking for now is the troubleshooting HV section (page 263 of the PDF). If somebody could point me in the direction of a complete scan or could scan a hard copy, I would really appreciate it.
Thanks,
Nick
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OT: Solartron 7071 for auction on UK eBay
I've just put a Solartron 7071 up for auction on UK eBay:
<>
Cheers
David Partridge
|
Great Bill!! Glad I could help.
I have 2 working 468s, and 2 parts units. The first working unit had bad PROMs when I got it, and several bad big electrolytic caps in the main power supply. The other working unit had a bad TTL clock oscillator in the microprocessor section, a bad U571 (if I remember correctly), and lots of minor problems like bad pots, broken knobs, etc. They both work and look great now.
When I get time, I enjoy fixing up old classic Tek and HP scopes. I use them from time-to-time. Last time I used the storage function on one of the 468s was troubleshooting on a PC's motherboard that had blown MOSFETs in the CPU power supply per bad electrolytics one the core supply's output.
Jimmy
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--- In TekScopes@..., "maninashed1" <bill.valvetechnology@...> wrote:
Hi Jimmy, and thank you for that information. Checked U571 - no problem, checked U558 op-amp faulty waveform present. In between is U352, a LF351 op-amp, this proved to be faulty and the source of the oscillation. New LF351 and scope now working fine again. Just needs a good service and thorough clean. Im going to keep this one, its a lovely bit of kit and is so useable for the things Im interested in. Thanks to everyone who took time to read this thread.
Bill
--- In TekScopes@..., "jtjewell83" <jtjewell83@> wrote:
Bill,
I'm wondering if that's noise from the D-to-A converter circuit, maybe because a low-pass filter cap is open. I'd suggest to check on the Storage Display Logic Board (A16), which is the top-most board. Check around op-amps U571A, U352 and U558. See if you've got that noise on the signals on pin 6 of those last 2 op-amps, and pin 1 of U571A. Oh, In between, there's a 250 kHz switching pulse on U523D. Hhhhuuummmm????
Jimmy
--- In TekScopes@..., "maninashed1" <bill.valvetechnology@> wrote:
Ive added some photos of the scope displaying the fault. These are in my photo folder under bill.valvetechnology.
Ive checked the waveforms and ripple from both power supplies against the manual and both the analogue and digital power supplies look fine.
Can anyone identify this fault? It has been suggested that it could be the clock signal being imposed on the waveform and the cursors in digital mode.
Thanks
Bill
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The 465b.djvu file (also at bama.edebris) has these pages in full.
-ls-
"nerritv" <neveenstra@...> wrote:
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Show quoted text
Hi,
I recently picked up a few nonfunctional 465b's as a pet project and
the one in question is of e low serial number variety. Anyway, I'm
looking for a complete set of the troubleshooting flowcharts. The
flowcharts in the manual on bama for the 465b are incomplete scans and
the portion in specific that I'm looking for now is the
troubleshooting HV section (page 263 of the PDF). If somebody could
point me in the direction of a complete scan or could scan a hard
copy, I would really appreciate it.
Thanks,
Nick
------------------------------------
Yahoo! Groups Links
|
NICK
For starters ther are two different manuals for the 465B depending
on serial number. The break point is at serial B060000.
You will need to tell us what serial unit you have so folks can get
yout he correct manual
If you don't come up with a free copy contact me off list, I have
professional reproduction quality scans of both versions of the
manual
Dave
Artkemedia
On 7/13/2012 9:15 PM, nerritv wrote:
?
Hi,
I recently picked up a few nonfunctional 465b's as a pet
project and the one in question is of e low serial number
variety. Anyway, I'm looking for a complete set of the
troubleshooting flowcharts. The flowcharts in the manual
on bama for the 465b are incomplete scans and the portion
in specific that I'm looking for now is the
troubleshooting HV section (page 263 of the PDF). If
somebody could point me in the direction of a complete
scan or could scan a hard copy, I would really appreciate
it.
Thanks,
Nick
--
Dave & Lynn Henderson
Manuals@...
PO Box 175
Welch,MN 55089
|
Hi,
I recently picked up a few nonfunctional 465b's as a pet project and the one in question is of e low serial number variety. Anyway, I'm looking for a complete set of the troubleshooting flowcharts. The flowcharts in the manual on bama for the 465b are incomplete scans and the portion in specific that I'm looking for now is the troubleshooting HV section (page 263 of the PDF). If somebody could point me in the direction of a complete scan or could scan a hard copy, I would really appreciate it.
Thanks,
Nick
|
David C. Partridge
David Hess