Re: Tektronix 585A Voltage Diagnoses Problem edited
Hi Randolph,
You checked all the tubes, but also the voltage reference tube V609? Should measure about 85 V.
The grid voltages of V 624 should be approximately equal, well within 1 V or so.
The voltage at the grids should be what you expect from the divider R615/616/617 with "your" -150V.
If the fault is elsewhere then likely you will find grid pin 7 far too negative and pin 6 (anode) far too positive, almost at "your" +100V. Then continue with V634.
Is the screen voltage about normal (not very negative)?
And so on (for now).
Albert
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Re: Q: covers for 555 power supply?
Sorry Jim. Try this url . This is his store. His email is mercedesmann at
Yahoo dot com.
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Re: 2247A PSU Troubleshooting
Chuck,
The only use of the linesman glove was to put the HT anode lead somewhere that would hold it from moving, and to keep it away from me. I never implied to wear them while working in electronics, they also have a leather shell glove to protect the linesman glove from damage.
But I do use latex gloves when doing this work, I'm not relying on them to protect me, but rather to add a weak safety net, since I have them lying around, they improve grip, and add a decent layer of uncertified protection, but they tear easily.
This reply is a little dated I know, haven't been following the thread for awhile.
NielsenTelecom
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Re: 11801C and the T1331 error: lost factory TB calibration data.
Mine has it and it's documented in the 11801 user and service manuals. The user reference manual on p 42 says:
"The signal from the calibrator output is a 250 mV square wave with a rise time of approximately 20 ps and a period of approximately 10 us."
I did a lot of work with it and my SD-26s until I found the SD-24. It was what go me hooked.
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Re: 2213A Novice, unsolved anomaly encountered, documented & video
Thank you for sharing your experiences!
toggle quoted message
Show quoted text
On Mon, Aug 26, 2019 at 12:38 PM guy232 <gry.russel@...> wrote: Apologies for the delay in updating, was a bit under the weather.
Months ago I initially used a 5x mag lens to investigate the solder joints
in the PS areas. Didn't see any issues.
Last week when I got back to working on this, I remembered I had a cheap
$20 usb microscope laying around.
Discovered very tiny cracks on all 3 pads on both Q946 and Q947. C907 had
crack on the component side of the board (the bottom was not cracked)
hosted pics of cracks:
IPA scrubbed, dried, applied some amtech flux and reflowed the joints.
Also swapped out C956, I was using the original mallory cap due to
ordering the incorrect cap the first time. Used a new Nichicon UHW 330uF
50V that I had on hand. I seen that C956 is listed as +10-100% and believe
this is a workable low impedance choice. If not, i'd appreciate any insight
on the matter.
Powered up, the shrinking H and V issue
and extreme intensity change fail states no longer occurs. The only fault
that I notice is that the traces just barely pulse brightness (as if you
were just barely turning the intensity knob by 1-2 degrees back and forth)
after 3-5min, they remains steady for until powered down.
Going to microscope a bit more and use a long wooden dowel to gently tap
around while the unit is running as David Hess mentioned on my project
thread on eevblog.
P.S.: Just adding a link to the project thread on eevblog in case it helps
anyone in the future etc.
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Re: 2213A Novice, unsolved anomaly encountered, documented & video
Apologies for the delay in updating, was a bit under the weather.
Months ago I initially used a 5x mag lens to investigate the solder joints in the PS areas. Didn't see any issues.
Last week when I got back to working on this, I remembered I had a cheap $20 usb microscope laying around.
Discovered very tiny cracks on all 3 pads on both Q946 and Q947. C907 had crack on the component side of the board (the bottom was not cracked)
hosted pics of cracks:
IPA scrubbed, dried, applied some amtech flux and reflowed the joints.
Also swapped out C956, I was using the original mallory cap due to ordering the incorrect cap the first time. Used a new Nichicon UHW 330uF 50V that I had on hand. I seen that C956 is listed as +10-100% and believe this is a workable low impedance choice. If not, i'd appreciate any insight on the matter.
Powered up, the shrinking H and V issue
and extreme intensity change fail states no longer occurs. The only fault that I notice is that the traces just barely pulse brightness (as if you were just barely turning the intensity knob by 1-2 degrees back and forth) after 3-5min, they remains steady for until powered down.
Going to microscope a bit more and use a long wooden dowel to gently tap around while the unit is running as David Hess mentioned on my project thread on eevblog.
P.S.: Just adding a link to the project thread on eevblog in case it helps anyone in the future etc.
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Re: Tektronix 585A Voltage Diagnoses Problem edited
Hi Randolph,
There is no reason to expect the plugin would pull the voltages off
their mark.
Get the -150V right and everything else should fall into line.
-Chuck Harris
randolphbeebe@... wrote:
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Hi Chuck,
The scope has a CA plug-in right now with a type 81A adapter. I am pretty sure all is good with the plug-in because the scope responds to the vertical position and input etc. I have a couple of the Type 81A adapters, I wonder if the present one may be causing problems.
Thanks for the
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Re: parting out 2) 7633's and a 7613 storage scope unless... $55 shipping each in US
Where do you have this stuff at?
NielsenTelecom
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Re: Tektronix 585A Voltage Diagnoses Problem edited
Thanks Roy,
My 585A does not have the black beauties but the red Erie caps that tested good in circuit. I replaced them all anyway this morning just in case there was cumulative leakage problems. No improvement yet so I will keep digging. I will post a schematic when I figure out how to.
Randy
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Re: Tektronix 585A Voltage Diagnoses Problem edited
Hi Chuck,
The scope has a CA plug-in right now with a type 81A adapter. I am pretty sure all is good with the plug-in because the scope responds to the vertical position and input etc. I have a couple of the Type 81A adapters, I wonder if the present one may be causing problems.
Thanks for the
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Re: Tek P6xxx probe reference question
Hi Dennis,
What I found in an accurate dimension for the probes is the diameter of the metal on the removable (replaceable) probe tip. Example - the P6137 (p/n 206-0378-00) is an accurate 3.5mm diameter.
I won't put good money on it but any other dimensions of the probe plastic parts is far too large.
I did come across a current link at the Tek site that covers probe replacement parts. It is at (selections at far right side of page). It seems to cover a fair cross-reference between probe models and diameters. You can also click on the scrunched diagram of the probe parts to expand to a
readable size. I saved the enlarged diagrams to a "Tek Probes" folder and PDF'd each page as well. You can never tell when things like this will disappear.
Part numbers and such for those items (i.e. probe tips, cables comp boxes) not called out on the probe-size-specific pages can be found on the first page by clicking on the link "Passive & Active Probe General Replacement Parts." It cross-references parts by each probe model number.
In all this brings all of the data on the probes together. I think I have all of my questions answered.
Thanks,
Greg
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Re: Tek P6xxx probe reference question
The full set of Tektronix catalogs are available in PDF form online at the TekWiki and other sites
They are very useful for determining specs, prices and when the various instruments were offered.
Dave
Sent from a small flat thingy
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On Aug 26, 2019, at 09:30, Richard Tyner <shawneesdad@...> wrote:
Hi Dennis. I don't have a catalog to see the probe pages you refer to in the last line in your post. By any chance could you please add them as a downable file? I have multiple probes and this would be very helpful.
Thanks and 73
Richard W4MCD
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FOUND (Re: WTB - Tektronix P6406 Word Recognizer Probe)
I found a P6406 last night. Thanks to everyone who replied. - Bill
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Re: Tek P6xxx probe reference question
Hi,
Perchance a Probewiki on the Tekwiki page?
larry
toggle quoted message
Show quoted text
On Aug 26, 2019, at 9:30 AM, Richard Tyner <shawneesdad@...> wrote:
Hi Dennis. I don't have a catalog to see the probe pages you refer to in the last line in your post. By any chance could you please add them as a downable file? I have multiple probes and this would be very helpful.
Thanks and 73
Richard W4MCD
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Re: Tek P6xxx probe reference question
Hi Dennis. I don't have a catalog to see the probe pages you refer to in the last line in your post. By any chance could you please add them as a downable file? I have multiple probes and this would be very helpful.
Thanks and 73
Richard W4MCD
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Re: FG502 Troubleshooting Help Requested
The charging and discharging currents for the timing capacitor have to pass through the switching circuitry of S155 so bad contacts there will stop the triangle generator working and the other waveforms all depend on the triangle generator. Measure the voltage drops across each of R140 and R175, this would show that the constant current sources are OK. Try this on different ranges since the current varies with the frequency range. The two voltage drops should be very similar. Measure the voltage at the junction of CR140/CR170 and at CR145/CR175, this shows whether the timing capacitor should be charging or discharging. Check that when you change the frequency dial the voltages at the outputs of U140 and U175 vary smoothly and approximately mirror each other, that should rule out a problem with the op-amps.
It sounds like you have a scope so monitor the emitter of Q210 while changing the frequency multiplier knob back and fore, you might see the occasional burst of activity even with poor contacts on S155.
There could also be a problem with the circuitry for externally gating the triangle generator, if Q315 is socketed you could remove it since it should be non-conducting in normal non-gated operation.
Roger
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Re: 11801C and the T1331 error: lost factory TB calibration data.
Reg,
If you are out for exotic toys, try finding 1180x or CSA803x with fast calibrator.
You can tell it apart visually by the calibrator jack being gold 3.5mm type instead of Nickel plated SMA.
It's basically a TDR part of SD-24 in a separate enclosure used instead of regular calibrator.
They are rare but not unique. Here's random example
I have never found who and why did this and why this is not documented anywhere.
Leo
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Re: Tek 576 Curve Tracer HV Transformer winding
Well - I did take some pictures.They can be seen here (scroll down):
The winding "machine" is built on a quite heavy brass plate
Cheers
Ulf Kylenfall
SM6GXV
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Re: Tek 576 Curve Tracer HV Transformer winding
7934? That's like asking a cupcake baker to whip up a 20 layer wedding cake...
I envision one 7934 tranny as taking a couple of days to make.
-Chuck Harris
Kyle Rhodes wrote:
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Hi Chuck,
If you could wind a new HV transformer for the 7934 (as I understand it's
the same one as the 7834), I'd gladly pay that for it.
Thanks,
Kyle
--
KSR Amps / Rhodes Amplification, LLC
Kyle Rhodes
(513) 480-2677
kyle@...
On Sun, Aug 25, 2019 at 10:45 AM Chuck Harris <cfharris@...> wrote:
If you guys are all willing to pay in the $200-300 range, like
the custom made stuff that was done for the 576, I'll start
winding again.
-Chuck Harris
Dave Daniel wrote:
And 547s and 7934s ...
DaveD
On 8/25/2019 8:12 AM, RustySparks wrote:
I wonder if the same company could make a batch of HV transformers for the 453
scope? I think several users of this group, including myself, have 453
scopes with
bad HV transformers.
Thanks,
Harry
-----Original Message-----
From: [email protected] <[email protected]> On Behalf Of
drawding@...
Sent: Sunday, August 25, 2019 1:25 AM
To: [email protected]
Subject: Re: [TekScopes] Tek 576 Curve Tracer HV Transformer winding
"Where do they get the cores to make a compatible transformer that
works in the 576
circuit. This is not a 115v 60 Hz transformer."
I believe that they make them in house. I sent them the original Tek
transformer
specification. I got the specification drawing from Bob Koller (now
posted online
as per this thread).
Thanks,
Dave
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Re: Tek P6xxx probe reference question
Hi Greg,
Yes, for many years it was not clear what Tek was doing with their probes.
I think the 3.5mm and 2.5mm probes were an attempt to make it clear from their description how big the probe diameter is rather than using less descriptive terms like "miniature" and "sub-miniature".
I believe the 2.5mm and 3.5mm reference is to the probe's ground ring diameter. I am not near any probes that I can check at the moment so I might be wrong about this. I must admit I never checked this until now, but I can point you to much more information on their probes and how Tek ended up with so many different probes.
Over the years there was a lot of pressure to:
1) Reduce the size (diameter mostly) of the probes so they could get into tighter spaces.
2) Reduce the circuit loading (capacitance mostly) from the probes.
3) Optimize the probe performance by designing some probes for specific scopes.
4) Create specialty probes for things like wafer probing, measuring digital signals with a logic analyzer. A more common example of these would be the P6015 High Voltage Probe or the P6021 current probe.
5) Provide enough accessories for each probe that the probes were very versatile.
Things really got really complicated in the mid-1980s when there were so many different probes that it was hard to know which probes worked with which instruments. That is when Tek included a few pages in their catalogs that showed which probes were recommended for which instruments and which could be used (but were not optimal).
Finally Tek had to do something better and towards the latter 1980s they added several pages to the probes section of their catalogs that explained the differences between the probes in a way that was helpful. What you should look for
is in the Probes section of the later Tek catalogs. Not every Tek catalog has this information but by about 1989 and onward there was a page devoted to showing each probe size (miniature, subminiature, 3.5mm, 2.5mm, etc) and EVERY part and accessory for that probe and how they were all attached. It includes part numbers for each item in the drawings.
I think the 3.5mm and 2.5mm probes were an attempt to make it clear from their description how big the probe diameter is rather than using less descriptive terms like "miniature" and "sub-miniature".
I often have to refer to these pages myself when I am trying to figure out which accessory goes with which probe.
Dennis Tillman W7PF
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-----Original Message-----
From: Greg Muir
Sent: Saturday, August 24, 2019 5:26 PM
I guess this is sort of an academic question about how Tek refers to their P6xxx probe series via a dimension.
In several probe accessory references Tek Refers to some probes in the series as "2.5mm" and others as "3.5mm" probes. I am trying to figure out to what part of the probe these dimensions apply. i can't seem to find any dimension on the probe body that comes close to those referenced except possibly the length of the bare tip. Could this be it?
Any ideas?
Greg
--
Dennis Tillman W7PF
TekScopes Moderator
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John Williams
guy232
bill K7WXW