开云体育

I realized that I didn’t see any CRT filament/heater glow in this newer 7603 so I put the working PSU in the other 7603 and in that scope I see the CRT is glowing. I can see a dot on the CRT screen for one second the moment I start it up then it’s gone. Got nothing on the horizontal deflection plates on this other older beat up 7603.

I would really like to get the newer 7603 up and running since it’s in very good shape and if got the readout board which my other 7603 is missing. I’m planning to use my 7L5 (which I was lucky enough to score on eBay recently) in this 7603.

I’ve replaced the CRT in the older 7603 before (it was cracked when I received it) and hoped that was the only problem with it but when it had some other issues and since it was lacking readout option I didn’t spend any more time on it.

Anyone who knows a spot where I could measure the 6,3VAC filament/heater for the CRT? Looks like it’s elevated almost 3kVDC above ground?!

On 04/27/2021 02:26 PM, Daniel Koller via groups.io wrote:

Hi folks, this is OFF TOPIC because it's about e-bay, but on the other hand, with the exception of my older gear, it's just about the only way I get *any* Tek or HP gear these days. So, with apologies if it drags on too long and in the wrong direction,....
I got a message from e-bay that explains they are changing their payment structure. According to that, sellers will need to directly link a bank account to e-bay so that they can receive payments directly from buyers. By May 21, if you do not link a bank account to e-bay, they will not allow new postings! So, the implication is that Paypal is no longer going to work.
I don't know about folks here, but I suspect, like me, they are a bit older, financially conservative, and are loathe to link a personal bank account to e-bay. To this day I do not have my paypal account "linked" to my bank account. I can have all my on-line accounts hacked, but none of them have any access to my bank account.
One thing I thought to do is open a small credit union account with low/no fees and use that only for e-bay / paypal and keep the balance low, just in case something gets hacked. But now I have to go to the bank, or perhaps open an account on-line. E-bay is NOT making it easier for the small seller. More and more e-bay is just becoming a venue for cheap Chinese goods and wholesale garbage.
So, just wondering what folks here plan to do about selling their old gear, and working with ebay in the future. Anyone have any good Ideas or workarounds to the e-bay problem, or an alternate e-venue for buying and selling old gear? E-bay has been a collector's and hobbyist's goldmine for 20 years. It's sad to see it continually changing for the worse.
I am sensitive to the fact that this is a topic only tangentially related to Tek or HP gear, so please keep replies relevant to how e-bay is a conduit for acquiring such gear for us. I'm happy to take replies off-group as well, but if it's relevant, I presume we all want to hear about it.
Thanks,
Dan

This started over a year ago. I don't think that in the end, buyers will no longer be able to use paypal. That would be a dumb move on ebay's part.

I couldn't wait to get switched. The only inconvenience I've found was of my own doing and I can change that at any time. I have two bank accounts and my ebay sales go into one and shipping is paid via paypal from the other. I can switch that but it's such a minor inconvenience that I'm not going to worry about. Both accounts are linked to paypal.

In the end, as a seller, I get more with managed payments than when the sales went thru paypal.

Vince.
--
K8ZW

Ebay sold off PayPal *years* ago so I'm not a bit surprised to see that
they've done this. Paypal also (at least used to) required that sellers
link their PP accounts to a bank account so I don't see that this is much
of a change except that PayPal is no longer the middle man. Early on,
PayPal was *notorious* from yanking back payments to sellers and taking the
money directly from their bank accounts without warning. I no longer sell
on E-bay but I do make many purchases there and I *always* pay for my
purchases with a CC so that I have *some* protection.

YMMV

On Tue, Apr 27, 2021 at 2:32 PM Daniel Koller via groups.io <kaboomdk=
[email protected]> wrote:

Hi folks, this is OFF TOPIC because it's about e-bay, but on the other
hand, with the exception of my older gear, it's just about the only way I
get *any* Tek or HP gear these days. So, with apologies if it drags on too
long and in the wrong direction,....
I got a message from e-bay that explains they are changing their payment
structure. According to that, sellers will need to directly link a bank
account to e-bay so that they can receive payments directly from buyers.
By May 21, if you do not link a bank account to e-bay, they will not allow
new postings! So, the implication is that Paypal is no longer going to
work.
I don't know about folks here, but I suspect, like me, they are a bit
older, financially conservative, and are loathe to link a personal bank
account to e-bay. To this day I do not have my paypal account "linked"
to my bank account. I can have all my on-line accounts hacked, but none
of them have any access to my bank account.
One thing I thought to do is open a small credit union account with
low/no fees and use that only for e-bay / paypal and keep the balance low,
just in case something gets hacked. But now I have to go to the bank, or
perhaps open an account on-line. E-bay is NOT making it easier for the
small seller. More and more e-bay is just becoming a venue for cheap
Chinese goods and wholesale garbage.
So, just wondering what folks here plan to do about selling their old
gear, and working with ebay in the future. Anyone have any good Ideas or
workarounds to the e-bay problem, or an alternate e-venue for buying and
selling old gear? E-bay has been a collector's and hobbyist's goldmine for
20 years. It's sad to see it continually changing for the worse.
I am sensitive to the fact that this is a topic only tangentially
related to Tek or HP gear, so please keep replies relevant to how e-bay is
a conduit for acquiring such gear for us. I'm happy to take replies
off-group as well, but if it's relevant, I presume we all want to hear
about it.
Thanks,
Dan

Brokerage accounts such as Fidelity and e-Trade have cash management features with check writing.
For some (I checked e-Trade), no minimum balance is required to open an account. Fees are generally zero (although I don't know about a cash management account with t tiny balance). The checks have routing numbers, just like a bank or credit union and you should be able to set up eBay payments to go directly to the account.

Henric,
I once had a 7603 with a problem intensity circuit. Turned out to be a failed transistor. .
Bob

I sell on Ebay and I had no worries linking my account.

Yes,
i have a separate bank account with just a few hundred dollars. So far no problems.
Bob

Dan,
I find my self in the same boat but I am also well studied in IT security as well. I would set up a separate bank account that is not a (MAIN) account and use that. If you wanted to insulate your Main account even further use a bank account at a different bank. there for no cross access. Also just a side note every time you hand out a paper check the routing number and the bank account number is printed on the bottom. It is less of an issue then is seems.

Eric

Hi folks, this is OFF TOPIC because it's about e-bay, but on the other hand, with the exception of my older gear, it's just about the only way I get *any* Tek or HP gear these days.? So, with apologies if it drags on too long and in the wrong direction,....
I got a message from e-bay that explains they are changing their payment structure.? ?According to that, sellers will need to directly link a bank account to e-bay so that they can receive payments directly from buyers.? By May 21, if you do not link a bank account to e-bay, they will not allow new postings!? ?So, the implication is that Paypal is no longer going to work.?
I don't know about folks here, but I suspect, like me, they are a bit older, financially conservative, and are loathe to link a personal bank account to e-bay.? ? To this day I do not have my paypal account "linked" to my bank account.? ?I can have all my on-line accounts hacked, but none of them have any access to my bank account.
?One thing I thought to do is open a small credit union account with low/no fees and use that only for e-bay / paypal and keep the balance low, just in case something gets hacked.? ? But now I have to go to the bank, or perhaps open an account on-line.? ?E-bay is NOT making it easier for the small seller.? More and more e-bay is just becoming a venue for cheap Chinese goods and wholesale garbage.
? So, just wondering what folks here plan to do about selling their old gear, and working with ebay in the future.? Anyone have any good Ideas or workarounds to the e-bay problem, or an alternate e-venue for buying and selling old gear?? E-bay has been a collector's and hobbyist's goldmine for 20 years.? It's sad to see it continually changing for the worse.
? ?I am sensitive to the fact that this is a topic only tangentially related to Tek or HP gear, so please keep replies relevant to how e-bay is a conduit for acquiring such gear for us.? ?I'm happy to take replies off-group as well, but if it's relevant, I presume we all want to hear about it.
? Thanks,
? Dan

I agree with Stephen. Use enough iron! If you use too small of an iron
you'll have to hold it on the board for too long while you wait for the
solder to heat up enough and melt and there's a good chance that you'll
overheat the board and cause the copper traces to lift. Also get a
temperature controlled soldering iron if you don't already have one. I
guarantee that it will make a marked improvement in your soldering
ability. And with a temperature controlled iron you almost can't use too
large of a soldering iron! If it fits, it will work!

Before you start make sure that the iron, the solder and the joint are
all as clean as possible! I use Kester 2% silver solder and it has a very
low melting point, 300F or so. It mixes with the original solder and lowers
the melting point so that I can quickly unsolder the joint and avoid any
chance of overheating the circuit board or the part. For unsoldering
something I set the iron at about 650 F and melt some of the solder onto
the tip of the soldering iron then apply the tip to the joint on the
non-component side of the circuit board. I already have my manual solder
sucker cleaned, cocked and ready to go. Once the solder on the joint is
thoroughly melted, not just the top melted, I use the solder sucker to pull
up the molten solder. If done correctly you shouldn't have to hold the iron
on the joint for perhaps two to three seconds and it will remove all of the
solder from the joint except for perhaps a very slight amount directly
between the lead and plated hole. I then use a small flat blade screwdriver
to push the lead sideways in the hole and break the lead free from the
plating if it's still attached. If I did the previous step correctly then
the lead is usually already completely free. It should take only a small
amount of force to break the lead free, don't force it. If it won't come
free then there's probably still solder on the reverse side of the board.
Only after I've checked and made sure that all of the leads on the part are
free do I lift the part away from the board. It should come free with no
force whatsoever. On double sided boards after you use the solder sucker,
you need to look at the reverse side and be sure that the solder there was
melted and removed as well. If it's not then you probably didn't wait long
enough after the solder started to melt to allow ALL of the solder (on both
sides of the board) to melt. If that's the case then you need to resolder
the joint and then desolder it all over again. I've never found any other
reasonable method of getting all of the solder off of the component side
other than resoldering and starting over again. I developed this method
while repairing circuit boards that could NOT be replaced at any cost and
that not damaging the boards was absolutely the top priority. Once I worked
out all of the materials and techniques it worked extremely well and I've
repaired thousands of boards using this method. FYI I've tried vacuum
operated solder suckers such as Pace brand but I still prefer one of the
manual ones. It's just easier to use even if I do have to manually cock it
each time. Keep the tip clean and pull the tip off every so often and clean
out the old solder inside of the sucker and regrease the piston and they'll
work on and on and on. I've acquired a few more of them as spares but I'm
still using one that I bought back in the 1970s. If it's operating
correctly, you can cock one then put your finger over to tip and then fire
it and the piston will back back part way but not all of the way due to the
vacuum inside of it and it will *hold* the vacuum.
I probably have or or have had at least one of every brand of soldering
iron out there and a wide variety of Pace and other soldering and
desoldering stations but I do most of my work using a regular Weller or
Hakko (929 IIRC) temperature controlled soldering iron and an antistatic
version of the Soldapullt solder sucker. I've also used the metal Paladin
solder suckers but for anything larger than a small joint I like the
Soldpullt because it's slightly larger and pulls more air. BUT, it's very
important IMO that you use a *top* quality solder such as Kester even when
unsoldering a joint. The Kester 2% silver loaded solder is hard to find and
is now stupidly expensive but it's by far the best solder that I've ever
used and I HOARD every bit of it that I can find and I use it very
sparingly. I won't waste my time trying to use lead free solder. FOR
ANYTHING!

I started out soldering, *and desoldering,* with a 200 Watt American
Beauty soldering iron with no temperature control. You should try that
sometime! I delaminated a lot of circuit cards!

Thanks everyone!! Doesn’t look so formidable a job now.

Bill

Hi Michael,

Last night my curiosity got the better of me and I searched for and found the DM501 schematics.

BTW, the Tek Wiki's DM501 (not DM501A) manual is incomplete, and I found one with complete, if unmerged, schematic pages. Good enough for my needs. But I should get this to the Tek Wiki admin to update. That's on me.

With that I brought in the plug-in which sacrificed itself for the cause. Along with its stink - that was a mistake, but it's cold out in the garage. I studied it against the schematics and board layout. Here's the dope: The trace that fried is not only connected to 33v common, but also traces back into the plug-in where it is grounded to the chassis. More careful examination of the failed trace does look like current was trying to travel down both branches to both "grounds". The connection to pin9B happened to loose first. But there's a distinct source from R421 that travels down both branches, one to 9B, the other to the chassis ground. So R421 seems to be the source of the current.

I did initially think: "the 33v common is ungrounded!" I ran back down to the garage, pulled out the TM504 and verified that indeed the 33v common has continuity to ground. A couple/few ohms due to connector grime? So it's not like the 33v common has something untoward on it. I did also verify the source fuses are correct capacity and type. I powered up the unit and verified the 33v common is at 0v relative to chassis ground.

Somewhat humorously, R421 is driven by a pot, R420 from pin 5 of U420, and R419 from pin 6 of U420. This is the 5v adjust. That circuit is driven by 12v derived from the +33v supply and a Zener, VR410, 12v. If VR410 opens, does the 12v rise and create over-voltage on the +12v supply in the plug-in? I would test, but I'm not plugging that thing back into a working PS unit quite yet.

The second plug-in that had started to burn had a singular trace from pin 7 (gnd) of a 7400 14 pin DIP. No apparent trace to chassis ground, nor any other component. I didn't dig too much deeper into that plug-in: DC504 (not A). The 7400 is one of many IC components driven of +5v derived from +33v by U405. Again, not powering that up any time soon to further debug.

So at this point the issue seems to be bad plug-ins, not something generally wrong with the power supply units. I do need better test equipment (working on that), and should find a better current detection setup before I go testing more plug-ins.

I should note these plug-ins are ancient. Many/most have calibration seals on them with due dates in the 90s - if not earlier. The seals on these two plug-ins were unbroken suggesting they haven't seen power in almost 30 years. As other recent experience has revealed, things do go bad just sitting in dry warm climates. Time to bust out a lightbulb setup? I also do have a vaiac that is due to arrive tomorrow. Just part of the learning process. The TM5xx series units are _not_ robust supply units. Rather quick-n-dirty cheap products. A little disappointing, but caveat emptor.

Dave

On Mon, Apr 26, 2021 at 10:39 PM, Alan Young wrote:

I have put a bid in on a 2246
which was rather low so I doubt that will happen.

If you will be considering one of the 224x line of scopes (2245/2245A, 2246/2246A, 2247A, and 2252A), I'd aim for the 2247A model, it has a couple of very useful additional counter/timer features over the 2246 like direct frequency/period readout which might be handy for amateur radio work, and this model should in most cases command a very similar price as the 2246/A. Or at the very least try to the the improved A version 2246. The next option would be the 2252A which is one up from the 2247A and the only difference is that the 52 has one additional blue button on the front panel labeled "Hard Copy" that allows to print the screen. But in all other respects the 2252A is exactly the same as the 2247A, although it does not come up for sale as often. I have owned a 2247A for 10 years now, and even though I have other scopes including a spec-wise much superior 2465B, the one that almost always gets fired up first is the 2247A as it is a very intuitive scope that has tons of nice and easy to use features. The only thing I had to do to it so far was to preemptively replace all the fast rectifier diodes as it is recommended, and twice the internal Lithium battery (the one that originally came with the scope was already dead). This scope also does not store any cal constants in volatile memory so the demise of the battery does absolutely not affect calibration.

All in all I'd say the 2247A is a nice middle ground between the lower cost design 22xx line and the higher tier 2465/67. Yes the 224x scopes power supply requites a bit of disassembly but nothing as complicated as the 2465. Even the 22xx line requires some disassembly to get to the power supply by removing the shielding cage and the bottom plastic cover, which sometimes can be a bear to remove, so no free lunch on any of these scopes in terms of working on recapping or repairing the power supply which is a given on scopes of this age unless the previous owner has gone fairly recently through the process.

On Tue, Apr 27, 2021 at 09:45 AM, Dave Peterson wrote:

In case you haven't already come across these things:

Here's the adapters Paul is referring to:

eBay listing number "273254508468".

I have used this seller's products for years. They are excellent. Also note that he has added a larger via to allow the use of "snap in" capacitors. This opens up another group of capacitors for your projects. His previous design used 3 small vias for + and - sides, those vias would only fit "standard" wire leads, snap in cap terminals would not fit. With the addition of the larger via ion the group, you can easily use snap in caps.

--
Michael Lynch
Dardanelle, AR

Hi Bill,

I slip a single ended hacksaw blade just under the cap, and saw off the lugs to remove the cap.? After that, very little heat is needed to remove the nubs from the board.

Make sure you do not leave any filings behind.

Good luck !

--
===============================
Scott Singelyn
Information Systems Manager
Flat Rock Metal, Inc.
26601 W. Huron River Dr.
Flat Rock, MI 48134-1090
Phone: (734) 782-4454 x 2660
Fax: (734) 782-5640
===============================

Dave,

What about "9A"? Any damage to that trace? Both 9A and 9B are tied to the 33.5 Common return. Are the fuses on the +33.5 Supply the correct "Fast Acting" fuses of the right current rating? I do not have answers to your other questions. I have never encountered or even heard of this phenomenon and I have several Power Modules as well as 2 dozen working plug ins.

The only way I have burned up a trace is when I plugged my flexible extender card to the module "upside down" (I know, DUMB Move!). I did have a few components go BOOM when i turned on the power. .

--
Michael Lynch
Dardanelle, AR

In case you haven't already come across these things:

Here's the adapters Paul is referring to:

eBay listing number "273254508468".



Seller is:



Or search for "Capacitor Adapter 15.5mm triangle".

Worth reading:

/g/TekScopes/files/Tek%20465%20Power%20supply%20Capacitor%20Replacement%20Guide%20-from%20web-/_Tek%20465%20Power%20Supply%20Capacitor%20Replacement%20Guide.pdf

Note that's from this groups files section. Search for "465 Power Supply Capacitor" to find it and others.

A message on this board where I describe the caps I selected to order from Mouser: /g/TekScopes/message/176235

If you go back to the beginning of that thread there's a link to a photo album showing a problem I encountered: /g/TekScopes/album?id=258720

The little trace circled in red in one picture shows the little jumper trace on the backside of A9 coming from C1512. It was the trace via from the front side to the back side that pulled out with the cap body when removing it. It didn't so much as pull out as disintegrate in tiny pieces that I didn't realize where there. I didn't find the problem until it was all reassembled and this little route wasn't reconnected. The solder wouldn't flow from the front to rear through the via without the trace material there. It was a bear to get fixed. Cautionary tail: continuity check all vias before reassembly. Repair damaged ones with copper tape. Available in mass quantities on Amazon.

Good luck and enjoy! It's very satisfying to recover a scope that's in good physical condition.

Dave

I've never had any problems but I have a Metcal setup. Suitable high end equipment (Pace, Metcal, etc) always helps.

Chipquick might be a good way to lower the melting point on those joints and minimize damage to the board.

And of course, use the little adapter boards to mate the modern snap cap to the 4 pin layout for the NLA original caps.

Paul

--
Paul Amaranth, GCIH | Manchester MI, USA
Aurora Group of Michigan, LLC | Security, Systems & Software
paul@... | Unix/Linux - We don't do windows

I have successfully changed all the caps in one of mine, a a few other as well.
I used a fairly powerful iron with a broad and thick tip. That will melt the solder very quickly, especially if you add some in the process for better heat conductivity. Suck the solder one pad at a time. When all the pads are done, reheat them a bit, one at a time, and slightly wiggle the cap from underneath. Do that very gently; some pads are also connected on the other side. If you don’t suck all the solder, you risk breaking the pad when pulling the cap. Remember to check all the connections on the other side of the board too.

Hope that helps.

Before I jump into replacing the low voltage power supply filter capacitors I wanted to see what technique others have used. My concern is damaging the circuit board. What is the best way to remove the solder while avoiding damaging the circuit board?
Thank you,
Bill