Date   

465 Scope Question

Bill
 

Started out with no -8vdc. Replaced the bridge rectifier now I have -6.5vdc. The power transistor Q1566 checks out as OK. Lifter C1569 but that didn't help. The voltages on Q1566 are ok except the Collector voltage is a little over =3vdc when it should be +5vdc. I'm going on the assumption that something downstream is dragging down the -8vdc but is not a dead short.

Sound reasonable?

All the other Low Voltage power supplies are dead on in voltage.
Bill


Unable to see some images in 75th anniversary consolidated pdf

Tommy
 

The subject line pretty much tells it: most images are there but some don't show on my computer (Howard's First Scope and World War Two, for example).
Anyone else seeing this or is it my computer ?

While they were presented one by one all were viewable but it would be nice to have the whole thing...


Re: 7L12 spur at 210MHZ - Request for test results or suggestions?

Jean-Paul
 

correction at 210 MHz I can see -100 dBm, above noise, no spurs at all anywhere 0-1500 MHz

Jon


Re: Good storage solution for collection of 500-series plugins?

Roy Thistle
 

On Sat, Apr 24, 2021 at 12:30 PM, - wrote:


I store my plugins in one of the silver colored ziplock anti static bags
If one is going to do that, either displace the air with dry nitrogen gas... which I assume everyone has... or put in a new (or properly salvaged) desiccant bag.
Here in the colonies, the military always seems to put them in.
If you don't... unless you live in the Mojave Desert.. you might regret it.

--
Roy Thistle


Re: Corrosion Damage – TM500 Plugins

Keith
 

Not to rub salt in the wound, but by coincidence just yesterday I was inventorying some electronic parts I have. They are stored in OEM packaging dated 1965. They were stored the old fashioned way, taped up in crinkle paper wrap. They have never been opened since 1965, so I opened one up just to check it.
The part was perfect. Bright shiny contacts, no corrosion, no funk, no issues. That’s 56 years, and no issues.

Like you guys and gals, I remember when the various kinds of foams became available. They looked cool, seemed to provide better protection against physical shock, etc., so I used them for a while, until I opened up an anvil case that had been stored for several years, and found a mass of goo-coated equipment...ruined by the degrading foam.

I went back to paper to wrap parts, and keep them in snap lid plastic containers. Sometimes I toss in a bag of silica gel, because the containers do breathe a bit. Yes, I take the risk of the static danger from the paper. If I am really worried about it I spray the paper with fabric softener and let it dry in the sun. The fabric softener eliminates the static threat.

Sometimes the old way is the right way. Try paper. It works pretty good.


Re: 465M

Ananda
 

Thanks, Tom and Michael. I will give those a try.


Re: 465M

Mlynch001
 

The circuitry for the DC restorer circuit is likely shorted. The 465M DC restorer is build in along with the HV multiplier as a unit of U550.

--
Michael Lynch
Dardanelle, AR


Re: 465M

 

Check the socket carefully. I have seen shorts develop between pins of the socket because of arcing and carbonizing.

On 4/24/2021 7:12 PM, adesilva_1999 via groups.io wrote:
The EHT section of the HV unit was ruled out with a separate tripler. It generates the 10kV required. The fuse blows only if it it connected to the CRT HV plug. I believe the current limiting (per the service manual) does not work for some reason. Hope to check out the transistors in that section along with the associated components tonight.




--
This email has been checked for viruses by Avast antivirus software.
https://www.avast.com/antivirus


Re: 465M

Ananda
 

The EHT section of the HV unit was ruled out with a separate tripler. It generates the 10kV required. The fuse blows only if it it connected to the CRT HV plug. I believe the current limiting (per the service manual) does not work for some reason. Hope to check out the transistors in that section along with the associated components tonight.


Re: Corrosion Damage – TM500 Plugins

Greg Muir
 


FS: 19 inch Atlas Audio 35U rack

Jim Ford
 

Hi, everybody.

I (foolishly) bought an audio rack thinking that I could put my rather large and bulky microwave gear in it. Fortunately I didn't actually try to mount anything it in, so the rack is in great shape. It's made by Atlas Sound, holds 35U of gear, has a front door, a rear door, and it's outside dimensions are 21.5 inches deep by 21 inches wide by 70.25 inches high. I bolted on casters so it can be rolled around. Black in color with kind of a crinkle finish. Photos on request.

I have it on OfferUp (newly merged with LetGo) for $250, but I'm happy to give a "good guy/gal" discount to someone in the group. Make me an offer.

No way do I want to ship this thing, but either you come pick it up in Laguna Hills, California where I live or I'll deliver it as far as LAX or San Diego. Maybe as far inland as Riverside or so.

Thanks!

Jim Ford


Re: Good storage solution for collection of 500-series plugins?

Renée
 

I do not know what it is but ( in general) things stored in steel cabinets and "cookie tins" seem to last a lot longer and without corrosion issues. I think it is due to the steel grabbing the reactive components in the air faster than the items stored, there is generally more surface area of the container to react......I do know my tea is stored in "tins" and lasts for years with little degradation due to oxidation. I believe it is the same reason.
Renée

On 4/24/21 12:30 PM, - wrote:
I store my plugins in one of the silver colored ziplock anti static bags
and then inside of a steel cabinet that has a drop down front door. The
cabinet is in a somewhat air conditioned room in an outbuilding. I've
never had a problem with the books, manuals, machine tools, wood, fabrics
or any of the electronics in there. I don't know that the cabinet was
originally made for but it's about 15 inches tall and has a single shelf so
isn't fitted for plugins but I stack then two of three high with no
problems ( I lay them on their sides just for stability.) Any decently
constructed enclosed steel storage cabinet with adjustable shelfs from Home
Depot or the like should work fine for storing them. But I do recommend
keeping them in antistatic bags just to keep any dust off and help prevent
ESD when handling them. Since they are electronic, I would avoid any
plastic storge containers or cabinets unless they're made of antistatic
material since plastics can generate static electricity. Depending on how
dry and/or cold your climate is, then that could be BIG problem or almost
insignificant in a hot, humid place like Florida.

On Sat, Apr 24, 2021 at 12:35 PM Jonathan Pyle <jhpyle@gmail.com> wrote:

I currently have four plugins for my RM45A (545A), which means three of my
plugins are always lying around somewhere collecting dust.

It would be great if there was a bookshelf or rack where I could store
plugins when I wasn't using them, where they would be enclosed on five
sides and thus protected from dust and other dangers.

Does anyone have a good solution for storing 500-series plugins? I was
hoping for something inexpensive rather than a vintage scope cart that
would cost a lot to ship. Maybe someone has found an Ikea-ish organizer
that happens to have compartments that are the perfect size for 500 series
plugins?







Re: Good storage solution for collection of 500-series plugins?

-
 

I went looking for a picture of a cabinet like mine but then realized
that a steel file cabinet would work fine for what you want. They're
available in single, double and four or five drawer models and you can get
them at any office supply store.

On Sat, Apr 24, 2021 at 3:30 PM It's me! <rrrr6789@gmail.com> wrote:

I store my plugins in one of the silver colored ziplock anti static bags
and then inside of a steel cabinet that has a drop down front door. The
cabinet is in a somewhat air conditioned room in an outbuilding. I've
never had a problem with the books, manuals, machine tools, wood, fabrics
or any of the electronics in there. I don't know that the cabinet was
originally made for but it's about 15 inches tall and has a single shelf so
isn't fitted for plugins but I stack then two of three high with no
problems ( I lay them on their sides just for stability.) Any decently
constructed enclosed steel storage cabinet with adjustable shelfs from Home
Depot or the like should work fine for storing them. But I do recommend
keeping them in antistatic bags just to keep any dust off and help prevent
ESD when handling them. Since they are electronic, I would avoid any
plastic storge containers or cabinets unless they're made of antistatic
material since plastics can generate static electricity. Depending on how
dry and/or cold your climate is, then that could be BIG problem or almost
insignificant in a hot, humid place like Florida.

On Sat, Apr 24, 2021 at 12:35 PM Jonathan Pyle <jhpyle@gmail.com> wrote:

I currently have four plugins for my RM45A (545A), which means three of
my plugins are always lying around somewhere collecting dust.

It would be great if there was a bookshelf or rack where I could store
plugins when I wasn't using them, where they would be enclosed on five
sides and thus protected from dust and other dangers.

Does anyone have a good solution for storing 500-series plugins? I was
hoping for something inexpensive rather than a vintage scope cart that
would cost a lot to ship. Maybe someone has found an Ikea-ish organizer
that happens to have compartments that are the perfect size for 500 series
plugins?






Re: Good storage solution for collection of 500-series plugins?

-
 

I store my plugins in one of the silver colored ziplock anti static bags
and then inside of a steel cabinet that has a drop down front door. The
cabinet is in a somewhat air conditioned room in an outbuilding. I've
never had a problem with the books, manuals, machine tools, wood, fabrics
or any of the electronics in there. I don't know that the cabinet was
originally made for but it's about 15 inches tall and has a single shelf so
isn't fitted for plugins but I stack then two of three high with no
problems ( I lay them on their sides just for stability.) Any decently
constructed enclosed steel storage cabinet with adjustable shelfs from Home
Depot or the like should work fine for storing them. But I do recommend
keeping them in antistatic bags just to keep any dust off and help prevent
ESD when handling them. Since they are electronic, I would avoid any
plastic storge containers or cabinets unless they're made of antistatic
material since plastics can generate static electricity. Depending on how
dry and/or cold your climate is, then that could be BIG problem or almost
insignificant in a hot, humid place like Florida.

On Sat, Apr 24, 2021 at 12:35 PM Jonathan Pyle <jhpyle@gmail.com> wrote:

I currently have four plugins for my RM45A (545A), which means three of my
plugins are always lying around somewhere collecting dust.

It would be great if there was a bookshelf or rack where I could store
plugins when I wasn't using them, where they would be enclosed on five
sides and thus protected from dust and other dangers.

Does anyone have a good solution for storing 500-series plugins? I was
hoping for something inexpensive rather than a vintage scope cart that
would cost a lot to ship. Maybe someone has found an Ikea-ish organizer
that happens to have compartments that are the perfect size for 500 series
plugins?






Re: 465M

Mlynch001
 

I would say that the High voltage multiplier is bad.

--
Michael Lynch
Dardanelle, AR


Re: Waking a slumbering 475

Tom Gardner
 

On 24/04/21 17:17, Jim Adney wrote:
Putting an incandescent lamp in series is a good troubleshooting method that can save you a lot of blown fuses. I think this was a method promoted in some audio amplifier kits, perhaps Dynaco. I never built any Dynakits, but the Heathkits I built never mentioned this. I probably picked it up from someone on one of the newsgroups I followed.
That technique is also used inside a couple of old Fluke DMMs, not least to protect against shorted NiCd cells.
https://www.eevblog.com/forum/testgear/fluke-8125a-military-dmm-teardown/msg2540730/#msg2540730


Re: Corrosion Damage – TM500 Plugins

-
 

I've been told that that foam breaks down and releases some kind of
Fluorine gas or compound. Whatever it is, it seems to attack just about
every kind of metal including stainless steel. Also gold, or possibly it
penetrates the gold layer and attacks the underlying metal.

There was a long discussion about this on the list a couple of months
ago.

On Sat, Apr 24, 2021 at 3:58 AM <christopherbath@hotmail.com> wrote:

Hi,

Sorry for the very long delay in replying. Inside the container is a black
open cell foam with comparatively large cells. The foam had not broken
down. It does appear the foam was glued in place and it is possible that
the glue may have caused the issue. The outside of the box is made from
plastic (possibly polyethylene). The case is almost airtight however would
still allow any external humidity into the storage container. On top of the
box was some other plugins with only a sheet of bubble wrap left on top of
them which are totally unaffected, so it is very likely that something
inside the box had caused the issue. The box from what I can tell is not
that old and the plug-ins had probably been in the box for about 5 years.

The damage is strange. I am not a chemist, and my knowledge of chemistry
is limited however the damage represents to me what I suspect is from a
gaseous corrosive chemical presumably that may have formed from either the
foam or glue possibly under summer conditions when the ambient temperature
may have exceeded 40 degrees Celsius (104 degrees Fahrenheit).

The damage included the following:

• Corrosion to steel components such as screws and the coating
(possibly zinc or similar)
• Oxidisation to aluminium including some small pitting in some
areas.
• Damage (reaction) to copper and brass from penetration through
plating such as nickel plated brass. Some tracks with silk screened
coatings on
top showed some very minor damage. Gold plated components feared
much better with almost no damage.
• Penetration inside some magnetically latching relays where the
chemical appears to have penetrated the epoxy potting causing corrosion to
some
of the mechanical parts.
• Accelerated damage where dissimilar metals had been in contact
such as the screws with the aluminium frame.
• Inside the one of the plugins there is a plated steel or iron
component that has had some of the plating come off. Obviously the chemical
had
penetrated the plating (which would be to some extent porous
anyway.
• Some “worming” to one aluminium front panel underneath the
anodized finish.

The modules were no better off being fully wrapped in bubble wrap inside
the container. The chemical also seems to have formed on the outside to the
plastic components however after cleaning with ethanol the plastic does not
appear to have been affected.

Any idea on what the chemical is that may have formed?

Thanks,

Chris






465M

Ananda
 

Gents,

Does anyone have any parts for a 465M by any chance? I had my scope start blowing the F558 fuse recently. It blows the fuse if the anode is connected. I had a spare CRT and that does the same thing. I also ruled out the EHT. Now it seems like something in the HV regulator area (per the service manual where the -2kV is controlled) has failed. I am yet to check the components there but there are some diodes that seem to be rare.

Any pointers/help is much appreciated.

Thanks in advance.


Re: 465 scope component question

Bill
 

Thank you. Yes it is blue. Mine has been physically damaged in the past so I need to replace it. I've also found several shorted Tantalums that I will be replacing. Good thing I enjoy tinkering!!
Bill


Re: 465 scope component question

Dave Peterson
 

C1477?
I have those too. Blue ceramic? The second larger one parallel to C1474 goes over to R1476/CR1476. Looks like C1477 to me.
Dave

On Saturday, April 24, 2021, 08:39:05 AM PDT, Bill via groups.io <ko4nrbs=yahoo.com@groups.io> wrote:

On the A9 Interface Circuit Board I ran into a problem identifying a component.  On page 198 of the service manual for scopes 250,000 and up at Position E3 near Q1474 note C1474, R1473, R1472 and CR1472.  In my scope there is a very small ceramic capacitor in front of what appears to be a large ceramic capacitor, could be C1474??  There are not two of them shown in the diagram in the manual.  The larger component has markings on it, CE .1k 200 volt, and is the component I'm not sure of.  Any ideas?
Thanks,
Bill

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