Date   

Cool videos on 570 Curve Tracer

David Berlind
 

I was not aware of this YouTuber (TomTekTests) until I stumbled across this video on a 570 restoration.

https://youtu.be/AphQLWbN8nI

Here is part 2:

https://youtu.be/U2GVbmi4Wso

Makes me want a 570 now. Although I have a 577 and an Eico 667 for which I intend to apply Dennis' mod (and I assume that it's much more flexible for testing a variety of tubes given all the socket types).


Re: Electrolytic Capacitor Removal NO Desoldering Required

 

On Wed, Apr 22, 2020 at 12:27 PM, M Yachad wrote:


I have repaired / overhauled HUNDREDS of SMD PCB's using this method, and
NEVER had a single issue of damage, ever.
Well said, Yachad, especially setting off professionalism against rigid traditionalism. Doing things in an unorthodox way can work!
You gave very clear instructions.
And you even express my stated opinion that **none** of the action must be lifting, just in-pcb-plane torsion for greatest safety.
You made my day!

Trying to kill the messenger (Mr. Carlson in this case) has always been a popular strategy to support an opposite opinion. BTW, like with most Youtube speech videos, I always play Mr. Carlson's videos (when I do) at x1.25 or x1.5 speed. Works very well.
It would be quite different of course if someone made the ridiculous claim of safely cleaning complete pcb's or even complete instruments with water and soap. Water and electronics don't go together! Hey wait, Tek used to do that from the Tube-scope days! Ah-well...

Raymond


Re: Electrolytic Capacitor Removal NO Desoldering Required

 

Regarding the issue of causing damage to the SMD pads, using this method.
Just goes to prove that there is no shortage of amateurs who call themselves "techs".

I have repaired / overhauled HUNDREDS of SMD PCB's using this method, and NEVER had a single issue of damage, ever.

There is a specific and EXACT technique to doing this ABSOLUTELY RIGHT.
1. Use ONLY bent-nose pliers, NEVER standard pliers. This ensures that you can apply DOWNWARD pressure safely during the entire operation.
2. You MUST apply MODERATE DOWNWARD pressure BEFORE starting the twisting action, and then CONTINUE to apply DOWNWARD pressure,while twisting.

This requires a specific mindset of concentration and focus to execute EXACT and PRECISION work, characteristics sorely lacking in the majority of "techs".

If you do NOT pay attention to the above 2 points, then you increase greatly the chances of damage.

You can always assess a tech's ATTITUDE to his work, by the number and types of mistakes he makes, while blaming his tools or the unit to be repaired.

Menahem Yachad
CondorAudio
Jerusalem Israel


Re: Tek built Interad SA

nonIonizing EMF
 

On Mon, Apr 20, 2020 at 10:37 PM, nonIonizing EMF wrote:


I'll message the seller to verify it's OK to use the images and update the
Tekwiki accordingly.
Received the OK to use the eBay listing photos, created the Interad 7121R wiki page ( http://w140.com/tekwiki/wiki/Interad_7121R ) and updated the Third Party Tek 5000 Series Scopes wiki page accordingly.


Re: Electrolytic Capacitor Removal NO Desoldering Required

Glenn Little
 

We got some hand me down Hitachi analog cameras for the NEWS department of the TV station that I was CE for.
NEWS just had to have the working cameras in the field NOW.
About 50% of the bad cameras had leaking electrolytic caps on the image blocks.
The electrolyte had leaked into in multilayer board and these cameras were scrapped.
It was not long before the working cameras became unrepairable due to electrolyte leaking into the multilayer boards.

Between these cameras and the DVC Pro decks, I replaced over two quarts of bad surface mounted electrolytics.

I got rather proficient at removing the capacitors with desoldering tweezers.
I do not know what they did after I left as I took my desoldering station with me.

I guess they farmed the board recapping out to contract repair.

Glenn

On 4/21/2020 10:01 PM, greenboxmaven via groups.io wrote:
Grabbing and twisting the entire condenser off the board seems very risly. Crushing and removing the can then going after the base seems to be a more reasonable idea. I have a few Sony Betacam portable VCRs that are loaded with bad and leaked condensers. The boards were drenched in electrolyte. I unsoldered them all, scraped the pads, then washed the boards in soapy hot water  before rinsing them and drying them in the hot box. Afterward, I tinned each pad and soldered the new condensers in place.  The recorder works perfectly.  I have done a couple IMAC G5s as well, they are still working fine.  Those bad condensers cause a lot of repairable gear to be trashed. I can understand commercial repair shops declining to repair them, but if you have time and patience, there is a lot of good stuff that can be restored.

      Bruce Gentry, KA2IVY






On 4/21/20 7:24 PM, victor.silva via groups.io wrote:
I saw this last year and didn't like when compared to my method that I have been using since 2005.
  First of all how can he say no soldering required when the old terminals are still there.
Obviously soldering is required to remove the terminals and clean up the pads.

I use a similar method but it puts absolutely no force on the pads.

I use angled cutters and cut the capacitor off at the bottom, around the collar, leaving the rubber seal, a tiny piece of aluminum and the plastic base.
The remaining rubber seal and plastic base comes off very easily now, by grabbing a corner with the cutters.

--Victor




--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"


Re: Electrolytic Capacitor Removal NO Desoldering Required

Glenn Little
 

So, what does conformal coating do to prevent leakage? Possibly hide the damage?
 Glenn

On 4/21/2020 9:31 PM, victor.silva via groups.io wrote:
Raymond,

Yes, after around serial number B066xxx (guesstimate) Tek started conformal coating their A5 assemblies.
The latest serial number on a 2465B, that I have seen, is B079xxx, from 1996.
The early B051xxx A5s had already started leaking, so the conformal coating was their solution.

--Victor

--
-----------------------------------------------------------------------
Glenn Little ARRL Technical Specialist QCWA LM 28417
Amateur Callsign: WB4UIV wb4uiv@... AMSAT LM 2178
QTH: Goose Creek, SC USA (EM92xx) USSVI LM NRA LM SBE ARRL TAPR
"It is not the class of license that the Amateur holds but the class
of the Amateur that holds the license"


2252 Vertical dc drift

marc.zed@btinternet.com
 

Hello. I have a 2252 scope with a fault thats driving me mad. Both channels 1 and 2 exhibit DC drift. ie. input is grounded, so centre the trace with the vertical position knob. Switch to DC coupled and the trace goes up to about 10 mV. As the scope warms up this increases
to about 60mV. Going back to grounded input brings the trace back to the normal preset position. Switch to AC input and the shift is still there only a slightly different value. CH3 and 4 seem OK although they have much reduced sensitivity so hard to see the shift.
I have the service manual but am drawing a blank. Any ideas or am I doing something really stupid?

Marc


Re: Vacuum forming 7K interface "covers"

teamlarryohio
 

200-0950-XX, IIRC
-ls-


Re: Electrolytic Capacitor Removal NO Desoldering Required

greenboxmaven
 

Grabbing and twisting the entire condenser off the board seems very risly. Crushing and removing the can then going after the base seems to be a more reasonable idea. I have a few Sony Betacam portable VCRs that are loaded with bad and leaked condensers. The boards were drenched in electrolyte. I unsoldered them all, scraped the pads, then washed the boards in soapy hot water before rinsing them and drying them in the hot box. Afterward, I tinned each pad and soldered the new condensers in place. The recorder works perfectly. I have done a couple IMAC G5s as well, they are still working fine. Those bad condensers cause a lot of repairable gear to be trashed. I can understand commercial repair shops declining to repair them, but if you have time and patience, there is a lot of good stuff that can be restored.

Bruce Gentry, KA2IVY

On 4/21/20 7:24 PM, victor.silva via groups.io wrote:
I saw this last year and didn't like when compared to my method that I have been using since 2005.
First of all how can he say no soldering required when the old terminals are still there.
Obviously soldering is required to remove the terminals and clean up the pads.

I use a similar method but it puts absolutely no force on the pads.

I use angled cutters and cut the capacitor off at the bottom, around the collar, leaving the rubber seal, a tiny piece of aluminum and the plastic base.
The remaining rubber seal and plastic base comes off very easily now, by grabbing a corner with the cutters.

--Victor



Re: Electrolytic Capacitor Removal NO Desoldering Required

 

On Wed, Apr 22, 2020 at 03:31 AM, victor.silva wrote:


Yes, after around serial number B066xxx (guesstimate) Tek started conformal
coating their A5 assemblies.
The latest serial number on a 2465B, that I have seen, is B079xxx, from 1996.
The early B051xxx A5s had already started leaking, so the conformal coating
was their solution.
Hi Victor,
My 2467B and 2467BHD are both in the B050XXX range, so it seems I've been very lucky!
I have no serial numbers of my other 2465B/67B's at hand.
My 2465 is Heerenveen-made, so no easy dating.

Raymond


Re: Electrolytic Capacitor Removal NO Desoldering Required

Jim Ford
 

Supposedly conformal coating prevents tin whiskers, too. I'm not convinced on either point.

Jim Ford

------ Original Message ------
From: "victor.silva via groups.io" <daejon1=yahoo.com@groups.io>
To: TekScopes@groups.io
Sent: 4/21/2020 6:31:49 PM
Subject: Re: [TekScopes] Electrolytic Capacitor Removal NO Desoldering Required

Raymond,

Yes, after around serial number B066xxx (guesstimate) Tek started conformal coating their A5 assemblies.
The latest serial number on a 2465B, that I have seen, is B079xxx, from 1996.
The early B051xxx A5s had already started leaking, so the conformal coating was their solution.

--Victor



Re: Electrolytic Capacitor Removal NO Desoldering Required

victor.silva
 

Raymond,

Yes, after around serial number B066xxx (guesstimate) Tek started conformal coating their A5 assemblies.
The latest serial number on a 2465B, that I have seen, is B079xxx, from 1996.
The early B051xxx A5s had already started leaking, so the conformal coating was their solution.

--Victor


Re: Electrolytic Capacitor Removal NO Desoldering Required

 

Hi Victor,

On Wed, Apr 22, 2020 at 02:36 AM, victor.silva wrote:


Louis is not repairing boards that have electrolyte leakage from capacitors.
I know. I was referring to the amazing improvement in copper trace bonding that has happened since the '70's when traces could easily be pushed away with a hot soldering iron.
The 2445/2465 families lie between the two extremes, timewise.

Most of the stuff he repairs is not even 6 years old.
I know, of course, see above.


My experience is mostly with the 2465B SM A5 assembly.
In many cases the pads are not even there anymore, the corrosion is so bad.
The twist method would only work on a 2465B SM A5 with no electrolyte damage,
which is very unusual.
Re. the twisting method, I was specifically referring to the TDS400/500/600 families, with many dozens of leaking caps each.
My most recent experience reconditioning a 2445/2465-family instrument (A5 caps, PS caps, mains filter caps, NVRAM/FRAM) is about 3 years ago.

My current instruments from that family are a 2465B, a 2467B and a 2467BHD. All have SMD-equipped A5's and none were so bad that pads were gone or even came off while working on them (yes, mostly using the twisting method). In fact, only the familiar matte solder surface gave away the leakage, no real corrosion visible.

I remember some other samples that were in much worse shape. I unsoldered some caps in those. Never lost a pad unless it was coming off already.


Only the very late >1993 A5s that were conformal coated
would show little damage.
My 3 units above certainly don't have conformal coating, if you're talking about a thick layer, covering the whole pcb. Never seen it on one of those instruments even. Nice!


I'm not going to be convinced to use the twist method. I've presented a method
that puts much less stress on the pads.
I doubt if perpendicular forces put less stress on the pads than forces almost purely in parallel with the pad/pcb interface.


I will let people decide to use what they want.
Thanks -;)

Raymond


Re: Electrolytic Capacitor Removal NO Desoldering Required

victor.silva
 

Louis is not repairing boards that have electrolyte leakage from capacitors.
Most of the stuff he repairs is not even 6 years old.

My experience is mostly with the 2465B SM A5 assembly.
In many cases the pads are not even there anymore, the corrosion is so bad.
The twist method would only work on a 2465B SM A5 with no electrolyte damage,
which is very unusual. Only the very late >1993 A5s that were conformal coated would show little damage.

I'm not going to be convinced to use the twist method. I've presented a method that puts much less stress on the pads.
I will let people decide to use what they want.

--Victor


Re: Vacuum forming 7K interface "covers"

Chuck Harris
 

They are little plastic covers, very thin, and about 1 inch by
3 inches. Their purpose is to restrain the free ends of the gold
socket pins.

They are simply a thin sheet of plastic that is bent to a specific
shape, probably with a vacuum forming method.

They are prone to getting longitudinal cracks, and when that
happens, they fall out, or simply stop retaining the socket
pins. Often the pins will get crumpled by the plugin after this
happens. At a minimum, they won't make uniform contact on all
pins.

-Chuck Harris

Roy Thistle wrote:

On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:


The plastic covers for the “fingers”
Are those (on a 7603) the white (nylon?) prismatic objects above and below the gold contacts... looking down into the 7603 bay? ... or maybe just a Tek part number?
Best regards.
Roy




Re: 465 tantalum smoke

Keith Erickson
 

You may be talking about

C891, or C893, or C897

All the same part number
290-0527-00
15uf 20V

You really need to acquire a SM

These caps you might say are a boot strap, just extra filtering, just my opinion

GL

Keith Erickson
Wayzata, MN

On Apr 21, 2020, at 6:30 PM, Rob Naulty <@ignatz> wrote:

Hi, I just received a 465 yesterday from Universal Radio, as another oscilloscope project. It was sold as not working at all and sure enough, all the voltages were low.
-8 was +.53v
+5 was +.57v
+15 was +.07v
+55 was +45.2v
+110 was 102.4v
-2450 was 0 v
As a note, I write everything down as I go thru the unit to help keep myself organized.
Next I was checking voltages at Q1546, Q1534, Q1566 and Q1556. The E and B voltages at Q1546 was very low, so I checked the voltage test points for resistance to ground, and the 15 volt test point went to ground.
As testing voltages again at Q1556, I "purposely" pushed my positive test lead to from one transistor lead to another. I started getting life into the CRT screen. More of a flickering and dull light, but an improvement over nothing.
So,I rechecked the voltages and here they are.
-8 now -7.15v
+5 now +3.05v
+15 now +5.30v
+55 now +49.4v
+110 now +102.9
-2459 now -2400v.....measurement taken with Simpson 260-3 ( I bought this from the original owner a couple of months ago. He asked me what I was going to do with the Simpson, and I told him I was working on Tektronix 453 and a 465. He smiled and told me that he used these scopes and then was talking to me about working on booster rockets at NASA for the Apollo series. Also he told me all the electrical connections in his timing boxes had welded terminal connections, not soldered.) Nice guy!.
Anyway I decided to turn the scope again and fool around with Q1546. The 15v transistor mounted on the side rail.
On Q1546 I touched C and B together and saw the CRT lightup and thick nasty smoke out of the side of the 465. I turned everything off and had to open a few windows. After the smoke cleared, I checked the voltages again. BTW...the smoke was intense.
-8 now -7.99v
+5 now +5.01v
+15 now +15.01v
+55 now +55.1v
+110 now +108.4
As I never owned a working oscilloscope or used one, its all a learning curve for me. I understand I have to replace that fried capacitor, but all the voltages are correct and I have two traces that I can move around.
On the side of the 465 right beside the on-off switch, there is three tantalum capacitors. The one that smoked was the one closest to the end of the board. (closest to the back of the 465). My serial # B321XXX shows its a newer one. I'd appreciate if someone could point me to the correct capacitor to order. The online manual for the 465 isn't as readable as the one for the 453.
I understand my oscilloscope skills might be in question, but it seems that one capacitor took the 465 down. I listen to older tube radios, like my SP 600 and HRO 60 and drifted to minor repairs and ended up interested in older test equipment. Just thought I'd pass my experience along, and if someone could tell me what tantalum to order.
Thanks, Rob



465 tantalum smoke

Rob Naulty
 

Hi, I just received a 465 yesterday from Universal Radio, as another oscilloscope project. It was sold as not working at all and sure enough, all the voltages were low.
-8 was +.53v
+5 was +.57v
+15 was +.07v
+55 was +45.2v
+110 was 102.4v
-2450 was 0 v
As a note, I write everything down as I go thru the unit to help keep myself organized.
Next I was checking voltages at Q1546, Q1534, Q1566 and Q1556. The E and B voltages at Q1546 was very low, so I checked the voltage test points for resistance to ground, and the 15 volt test point went to ground.
As testing voltages again at Q1556, I "purposely" pushed my positive test lead to from one transistor lead to another. I started getting life into the CRT screen. More of a flickering and dull light, but an improvement over nothing.
So,I rechecked the voltages and here they are.
-8 now -7.15v
+5 now +3.05v
+15 now +5.30v
+55 now +49.4v
+110 now +102.9
-2459 now -2400v.....measurement taken with Simpson 260-3 ( I bought this from the original owner a couple of months ago. He asked me what I was going to do with the Simpson, and I told him I was working on Tektronix 453 and a 465. He smiled and told me that he used these scopes and then was talking to me about working on booster rockets at NASA for the Apollo series. Also he told me all the electrical connections in his timing boxes had welded terminal connections, not soldered.) Nice guy!.
Anyway I decided to turn the scope again and fool around with Q1546. The 15v transistor mounted on the side rail.
On Q1546 I touched C and B together and saw the CRT lightup and thick nasty smoke out of the side of the 465. I turned everything off and had to open a few windows. After the smoke cleared, I checked the voltages again. BTW...the smoke was intense.
-8 now -7.99v
+5 now +5.01v
+15 now +15.01v
+55 now +55.1v
+110 now +108.4
As I never owned a working oscilloscope or used one, its all a learning curve for me. I understand I have to replace that fried capacitor, but all the voltages are correct and I have two traces that I can move around.
On the side of the 465 right beside the on-off switch, there is three tantalum capacitors. The one that smoked was the one closest to the end of the board. (closest to the back of the 465). My serial # B321XXX shows its a newer one. I'd appreciate if someone could point me to the correct capacitor to order. The online manual for the 465 isn't as readable as the one for the 453.
I understand my oscilloscope skills might be in question, but it seems that one capacitor took the 465 down. I listen to older tube radios, like my SP 600 and HRO 60 and drifted to minor repairs and ended up interested in older test equipment. Just thought I'd pass my experience along, and if someone could tell me what tantalum to order.
Thanks, Rob


Re: Electrolytic Capacitor Removal NO Desoldering Required

 

On Tue, Apr 21, 2020 at 10:59 PM, Brendan wrote:


I replaced the surface mount caps on my TDS420 with that method. Every twist
made my heart race. It worked. Did I like doing it? Nope. If I would have had
tweezers I would have used those for sure. You still have to wipe off the pad
with an iron to remove the left over lead that you twist off so you don't
really save the pad from any heat cycles. I also had a really hard time
getting a good thermal transfer due to the leaked electrolytic even after
trying to clean with a scratch pen.
Several years ago, I sidestepped into TDS400/500/600 land. Many in those series suffered from the leaking caps syndrome.
I must have "unscrewed" hundreds of caps and never lifted a pad. The bonding of the pads is very much stronger than it was with 70's PCBs.

I have watched some of the Mac laptop repair videos by Louis Rossman and was astonished what amount of hot rubbing and scraping the pads can endure. To think that in the 70's, normal quality copper pads could be just pushed across the epoxyglass substrate at soldering iron temperatures.

These days I own a fine Weller tweezer but I don't think I'd prefer using that. Unscrewing is effortless and quick.
I think I read someone recommend pulling while turning. I don't think that's a good idea. It defeats the idea of tearing (shearing?) the legs from/across the pad in parallel with the bond layer.
After removing the cap, the remaining solder and electrolyte residue can be removed from the pads by rubbing with a hot iron and flux, unless the pads have been damaged too much. Finish by cleaning the board. I can recommend having a look at how Louis performs his Mac repair work, it may surprise you. He's pretty rough on the boards but doesn't seem to do damage often.

Raymond


Re: Electrolytic Capacitor Removal NO Desoldering Required

victor.silva
 

I saw this last year and didn't like when compared to my method that I have been using since 2005.
First of all how can he say no soldering required when the old terminals are still there.
Obviously soldering is required to remove the terminals and clean up the pads.

I use a similar method but it puts absolutely no force on the pads.

I use angled cutters and cut the capacitor off at the bottom, around the collar, leaving the rubber seal, a tiny piece of aluminum and the plastic base.
The remaining rubber seal and plastic base comes off very easily now, by grabbing a corner with the cutters.

--Victor


Re: Vacuum forming 7K interface "covers"

Roy Thistle
 

On Tue, Apr 21, 2020 at 11:16 AM, Eric wrote:


The plastic covers for the “fingers”
Are those (on a 7603) the white (nylon?) prismatic objects above and below the gold contacts... looking down into the 7603 bay? ... or maybe just a Tek part number?
Best regards.
Roy