Date   
Re: DC-508 repair advice

radioconnection@...
 

It's working fine now... the transistor fixed it; but I was a few bucks on the ECL chip replacement.

Next project is a TM-504 auction site special.... BOTH 18,000 uF filter caps are open! ESR=infinity.
508 is in a good TM-503 for testing.

Re: DC-508 repair advice

Ed
 

Make sure that Switch S1380 (section 13) is turning ON when selecting the prescaler. Measure 5V on U1570B pins 6 and 7. I just repaired a DC502 that had the prescaler select switch switch stuck in the ON position (which disabled the prescaler), maybe the lever arm for this one is stuck OFF.

Re: DC-508 repair advice

Mlynch001
 

Sometimes the very simple things are the issue. My TYPE576 was knocked out buy a single 2N3906 that failed. Good luck with your repair.

--
Michael Lynch
Dardanelle, AR

Re: DC-508 repair advice

radioconnection@...
 

Q63 a 2N3906 level converter was bad...

Re: TG501 Option1 Oscillator Y50 needed.

Mlynch001
 

THANK YOU!

--
Michael Lynch
Dardanelle, AR

Re: Mylar Tektronix photos from 1950’s and 60’s fro eBay

Greg Muir
 

Given dimensions are in inches I suspect that the autopositives and the one negative were for use at the Beaverton plant. The indication of a Netherland reference on the negative may have been for a batch of completed panels destined to be shipped to their offshore plant for final assembly.

Photo anodizing is a significant process to maintain and I suspect that the Netherlands plant may have not possessed that function. Manufacturing processes requiring large overheads are usually located a one central plant with the lower cost manufacturing, mostly assembly related, being distributed to other locations when desired. Assemblers are a much cheaper commodity.

Greg

Re: TG501 Option1 Oscillator Y50 needed.

 

Hi Michael,
I can send you one I took out of a 7K plugin.
Contact me off line at dennis at ridesoft dot com.
Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Mlynch001
Sent: Friday, December 13, 2019 8:44 AM
Subject: [TekScopes] TG501 Option1 Oscillator Y50 needed.

I have a TG501 with Option #1 and I need Y50 5Mhz Oscillator which is TEKTRONIX p/n 119-0262-00 or 119-0503-00. These are also used in 7xxx series plugins and other TM5xx plug ins as well. I have looked at the usual sources, including Sphere's online catalog and E-Bay as well, no luck so far. Does anyone have an extra unused part that they would be willing to sell? I would be more than happy to pay a reasonable price and shipping to anyone who might have one. I would prefer an item located in the USA, but would consider anything that is offered. I can pay through PayPal.
I have also read a couple of posts regarding this part and discussion about using some very common 10Mhz OCXO part to replace it. I am not 100% clear on how this is done, ISTR this involved using a 5V regulator to step down the 15V to 5V and rewiring the U50 divider to divide the 10Mhz down to 1 Mhz. Dennis Tillman touched on this in a post, I believe regarding a TM5xx series counter which he improved the performance of, using this method. I am not as experienced as Dennis, so what seems obvious and simple to most is somewhat more daunting to me. I would also consider this route, if I could get some more details, possibly a schematic, pictures and a BOM?

Thanks to All!
--
Michael Lynch
Dardanelle, AR




--
Dennis Tillman W7PF
TekScopes Moderator

TG501 Option1 Oscillator Y50 needed.

Mlynch001
 

I have a TG501 with Option #1 and I need Y50 5Mhz Oscillator which is TEKTRONIX p/n 119-0262-00 or 119-0503-00. These are also used in 7xxx series plugins and other TM5xx plug ins as well. I have looked at the usual sources, including Sphere's online catalog and E-Bay as well, no luck so far. Does anyone have an extra unused part that they would be willing to sell? I would be more than happy to pay a reasonable price and shipping to anyone who might have one. I would prefer an item located in the USA, but would consider anything that is offered. I can pay through PayPal.
I have also read a couple of posts regarding this part and discussion about using some very common 10Mhz OCXO part to replace it. I am not 100% clear on how this is done, ISTR this involved using a 5V regulator to step down the 15V to 5V and rewiring the U50 divider to divide the 10Mhz down to 1 Mhz. Dennis Tillman touched on this in a post, I believe regarding a TM5xx series counter which he improved the performance of, using this method. I am not as experienced as Dennis, so what seems obvious and simple to most is somewhat more daunting to me. I would also consider this route, if I could get some more details, possibly a schematic, pictures and a BOM?

Thanks to All!
--
Michael Lynch
Dardanelle, AR

Re: 602 (XY) CRTs

kc0wox Leeper
 

Here's some info on repairing 620's. http://golddredgervideo.com/kc0wox/tek/620/ It had a crt dot but it might help you.
Leonard

602 (XY) CRTs

toby@...
 

Hi group,

I'm refurbishing a 602 with no spot visible (with Z input driven at ~
1V). All LV voltages are good. Waiting for a high voltage probe in order
to do more checks.

I want to keep a spare CRT on hand just in case, and I'd prefer it to
have P7 or P45 phosphor.

I also have 634 and 604 here. Does anyone know the CRT compatibility for
the various 6xx family models? Ebay hasn't turned up a 154-0562-01 or
154-0572-01 yet, but if there is wider compatibility it would be
interesting to know.

Thanks for any guidance on 602 troubleshooting or CRTs.

--Toby

Re: 1502 TDR project - using bench supply

Tom Gardner
 

On 13/12/19 02:54, ehsjr via Groups.Io wrote:
On 12/12/2019 3:59 PM, Mark Pilant wrote:
So, here is a list of what I tried and whether or not it "worked":
    1)   Used the TekWiki cap/resistor replacement for the battery.  Did not work.
Two things come to mind on that.
First, do not attempt to power on the 1502 immediately after plugging
in the AC cord or wall wart supply.  Give it a few seconds to charge
the cap, then turn the 1502 on.

Second, the cap may be too small.  I used 4700uF which works
fine for me - I think the wiki recommends 2200.
The problem is that if the capacitor is too large it takes too long to charge up. The PSU interprets the low voltage as a failed cell, and shuts down.

The required C (and R) seems to be select-on-test, varying from one 1502 to another. Even if suitable values are found, it makes me wonder if it will switch on /next/ time :(

Re: 1502 TDR project - using bench supply

ehsjr
 

On 12/12/2019 3:59 PM, Mark Pilant wrote:
Success.
After using the bench supply, and giving the unit a couple of minutes to warm up,
I started rotating the intensity control. As I swept to the upper end, I could see
evidence of a trace, although off the CRT. By adjusting the vertical position, I
was able to finally see the trace on the CRT.
I decided to check a couple of RG-58 test cables I had laying around, and the TDR
got them right.
So, here is a list of what I tried and whether or not it "worked":
1) Used the TekWiki cap/resistor replacement for the battery. Did not work.
Two things come to mind on that.
First, do not attempt to power on the 1502 immediately after plugging
in the AC cord or wall wart supply. Give it a few seconds to charge
the cap, then turn the 1502 on.

Second, the cap may be too small. I used 4700uF which works
fine for me - I think the wiki recommends 2200.

Finally, if using an external supply (wall wart or otherwise),
put a diode in series between the supply and the cap/resistor
combo. The diode is to protect the 1502 against plugging in a
wall wart or supply with the opposite polarity, and protect "backfeeding" the wall wart or supply. The TDR tries to put
about 17 volts across the bananna jacks to charge the battery.

Ed

<snip>

Re: Mylar Tektronix photos from 1950’s and 60’s fro eBay

 

On Thu, Dec 12, 2019 at 10:41 PM, John Griessen wrote:


must mean it is for eindhoven Netherlands. Tek had a factory at Heerenveen,
so maybe the customer was in eindhoven?
Dutch Philips' main offices were in Eindhoven.

Raymond

Re: Trying to save a 576

Mlynch001
 

On the HV board, find Pin G, disconnect the wire and put your ammeter in-line. You should get a baseline reading when you first turn it on. As the unit warms up you should see the current draw slowly increase (if the HV transformer is shorted). This is the 100V Supply, but it affects the entire system when it overloads the main transformer.
--
Michael Lynch
Dardanelle, AR

Re: Trying to save a 576

Mlynch001
 

Eric,

I’m not saying that I am 100% correct about this, it just sounds exactly like what my unit did as well.

--
Michael Lynch
Dardanelle, AR

Re: Trying to save a 576

Mlynch001
 

That is my guess as to the problem. Mine did exactly the same thing. I have a very old one and a very late model one as well. The old one had the Brown transformer, the new unit has the Black one. I found the power in wire to the HV transformer and put an ammeter in-line to read the current draw. I will look at the schematic and tell you which wire I used. What mine did was started out at a low current draw , the unit worked fine, and as it heated up, the draw slowly increased until the power supply finally tripped. I don’t remember the exact current draw numbers. BTW, I have a prototype transformer in the works to replace the brown transformers. I will put you down on my list as potentially needing a replacement for yours.

--
Michael Lynch
Dardanelle, AR

Re: 1502 TDR project - using bench supply

Greg Muir
 

Ignacio,

Oops! Fumble fingers here. The correction has been made.

Thanks!!

Greg

<<<<<
Ignatio EB4APL mentioned:

Greg,

After searching for your album, I realized that there is typing error in the name, "Tex" instead of "Tek"

Regards,

Ignacio

Re: Trying to save a 576

Eric
 

This one does for sure the brown potted one. The serial number is 22XXX. I would have never guessed that one would have spent the night banging my head agents the power supply. Is there a test I can do to confirm the transformer?

Re: Mylar Tektronix photos from 1950’s and 60’s fro eBay

John Griessen
 

On 12/12/19 3:24 PM, John Williams wrote:
would appreciate it if someone out there could shed any light on purpose, origin, etc.

That mostly black film is a tooling film for making
photosensitive prints by contact probably. It's what patterned
the resist for an aluminum anodized front panel.

FOR HOVEN MOD MONTEK

must mean it is for eindhoven Netherlands. Tek had a factory at Heerenveen,
so maybe the customer was in eindhoven?

Re: Trying to save a 576

Mlynch001
 

HV transformer is going out. Look to see if it has the brown encapsulated HV transformer.
--
Michael Lynch
Dardanelle, AR