Date   

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 <cfharris@...>
 

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 <rdnault851@msn.com> 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


Re: Scope Probe to BNC Adaptor

Roy Thistle
 

On Mon, Apr 20, 2020 at 02:01 PM, David Kuhn wrote:


I
have one (which is kind of flakey) and want more.
Just curious... with the thumb screw and all... do they damage or mark the probe's "ground ring"?... they seem a bit brutal on the probe?
Roy


Re: Scope Probe to BNC Adaptor

Roy Thistle
 

On Mon, Apr 20, 2020 at 10:58 PM, satbeginner wrote:


Or maybe these from in China
Yes.. I have some... they are okay on the end of a good flexible coax, with a barrel adapter/connector inbetween... but, don't work out very well if you hang a probe from them, on an instrument's panel mounted bnc.
Roy


Re: Electrolytic Capacitor Removal NO Desoldering Required

Roy Thistle
 

On Tue, Apr 21, 2020 at 01:43 PM, Paul Amaranth wrote:


Also can he use a larger soldering iron?
I'm not sure if I know what you mean... but, according to his other videos... he likes to have a high thermal transfer rate... for a relatively low iron temperature... so he sometimes uses lower temperature whacking great irons, on little stuff. He likes to... and claims to have no problems with... soldering onto battery terminals...using that technique. Never worked for me so far (battery always fail prematurely... as it seem to do some kind of damage, whether visible or not.) On pcbs, I guess you don't want to completely melt, or boil away the epoxy adhesive, under the copper traces?
Roy


Re: Tek 177

Eric
 

Sorry about the noise Dave thank you for all that you do your Manuals have saved my butt a few times.

On 4/21/2020 6:27 PM, ArtekManuals wrote:
OK you have my attention though goodness knows why?

The 177 is the "Standard test fixture" for the 577. It is included in the 577 operators manual and has a separate stand alone service manual

Dave
ArtekManuals

On 4/21/2020 1:26 PM, Colin Herbert via groups.io wrote:
Eric,
I think there are a couple of inconsistencies/mistakes here.

The title of your post is "RE: [Tekscopes] Artek Manuals", but it has nothing to do with Artek Manuals.
You start off mentioning a 577, but then go on to mention a 177 twice. As far as I am aware, there is no Tek 177.

I also think that Tam is advising the OP NOT to scrap the 577, so your request is possibly out-of-place.

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Eric
Sent: 21 April 2020 18:13
To: TekScopes@groups.io
Subject: Re: [TekScopes] Artek Manuals

If you are scrapping out a 577 I am in need of a high voltage cap from the 177 or would be interested in the whole 177 if it is available.


On Wed, Apr 15, 2020, 10:02 AM Tam Hanna <tamhan@tamoggemon.com <mailto:tamhan@tamoggemon.com> > wrote:

Hello,

on the risk of a beating: if you want to scrap the 577 because of a dead
CRT, do NOT do it.


A fix is forthcoming. Send an e-mail OFF LIST, saying STINKELY.


Tam


Re: Electrolytic Capacitor Removal NO Desoldering Required

Roy Thistle
 

On Tue, Apr 21, 2020 at 03:01 PM, Sam Reaves wrote:


I tried it on some scrap boards - I don't recommend it.
Well... IMHO the crux of it is... when they are leaky... or about to leak... and have disgorged... or will soon disgorge, corrosive electrolyte... how do you get them off, without getting more of the electrolyte... or heating/baking... the electrolyte that is on there already... and how do you de-solder them... without excess iron dwell time... when the solder has been "poisoned" by the leaked electrolyte? So, Mr. Carlson is implying/suggesting the method he shows is a kind of trade off?... sort of damned maybe, if you do... and damned maybe, if you don't.
Roy


Re: Electrolytic Capacitor Removal NO Desoldering Required

 

I like the guy because I see on the right what appears to be two 547 scopes side-by-side. Good choice!
I don't know where he lives, but hopefully he is not where he is in the video if an earthquake strikes and all that heavy hardware he is surrounded with falls on him.

Ernesto


Re: Electrolytic Capacitor Removal NO Desoldering Required

Dave Wise
 

[re Mr. Carlson YouTube]
He irritates me too. Lots of subtle misinformation delivered with supreme confidence and way too many words.
I watched one video and said "Well, there's <xxx> minutes of life I won't get back."

Dave Wise
________________________________________
From: TekScopes@groups.io <TekScopes@groups.io> on behalf of Roy Thistle via groups.io <roy.thistle=mail.utoronto.ca@groups.io>
Sent: Tuesday, April 21, 2020 3:06 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Electrolytic Capacitor Removal NO Desoldering Required

On Tue, Apr 21, 2020 at 01:43 PM, Paul Amaranth wrote:


A lot of people seem to like him
Not me... I find him irritating.
Roy


Tek 177

ArtekManuals <manuals@...>
 

OK you have my attention though goodness knows why?

The 177 is the "Standard test fixture" for the 577. It is included in the 577 operators manual and has a separate stand alone  service manual

Dave
ArtekManuals

On 4/21/2020 1:26 PM, Colin Herbert via groups.io wrote:
Eric,
I think there are a couple of inconsistencies/mistakes here.

The title of your post is "RE: [Tekscopes] Artek Manuals", but it has nothing to do with Artek Manuals.
You start off mentioning a 577, but then go on to mention a 177 twice. As far as I am aware, there is no Tek 177.

I also think that Tam is advising the OP NOT to scrap the 577, so your request is possibly out-of-place.

Colin.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Eric
Sent: 21 April 2020 18:13
To: TekScopes@groups.io
Subject: Re: [TekScopes] Artek Manuals

If you are scrapping out a 577 I am in need of a high voltage cap from the 177 or would be interested in the whole 177 if it is available.


On Wed, Apr 15, 2020, 10:02 AM Tam Hanna <tamhan@tamoggemon.com <mailto:tamhan@tamoggemon.com> > wrote:

Hello,

on the risk of a beating: if you want to scrap the 577 because of a dead
CRT, do NOT do it.


A fix is forthcoming. Send an e-mail OFF LIST, saying STINKELY.


Tam
--
Dave
Manuals@ArtekManuals.com
www.ArtekManuals.com
--
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