Date   
TM504 Front Panels

 

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dennis Tillman W7pF
Sent: Tuesday, June 02, 2020 1:59 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

Hi Michael,
You are correct. Those plugins and many of the newer "A" versions of the DM5xxA models have a more complex front panel.
But the plugins with complicated 3D extruded front panels make up less than 10% of what was made.
A blank front panel with the front area recessed (and a flat backside) will make it possible to restore the appearance of a lot of otherwise perfectly working plugins with damaged front panels Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Michael W. Lynch via groups.io
Sent: Tuesday, June 02, 2020 7:38 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

Dennis,

Taking a very cursory look at a few TM500 plug ins, I see some issues here, For example, my PG506 and DM502A (surely others as well?) have a very complex back plane with mounting bosses as well as screws that come in from the sides, with threaded inserts. In themselves, These are not insurmountable, however, it does make for a much more complex 3D printing problem, mainly because of the dimensional accuracy required for proper alignment of all the parts. Later design Plug ins are not flat on the front or the back sides e.g. there are recesses and/or protrusions on both sides.

Perhaps there are some that are less complex that you could suggest that would be better candidates??

I am not going to abandon the idea, but it will take some time to figure out the best way to approach the problem .

--
Michael Lynch
Dardanelle, Arkansas





--
Dennis Tillman W7pF
TekScopes Moderator





--
Dennis Tillman W7pF
TekScopes Moderator

TM504 Front Panels

 

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Mlynch001
Sent: Tuesday, June 02, 2020 4:43 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

Dennis wrote:
It may not be necessary to recess it on the back side to make the design simpler.
On the front it would be highly desirable to have a small hole on every panel for the pull tab to go through.
I found a blank I can send you
Dennis,

Please do send it to me. I will get this designed and print a prototype. I will make sure that you get your sample back after the design phase is completed.

I can provide a rectangular hole for the pull tab and also any other holes that would be present on ALL versions of plug ins. I believe that there are some holes that must be common to all versions. Possibly the 4 screws that hold the front panel to the upper and lower aluminum extrusions?

Looking forward to getting this part designed and printed.

Thanks!

--
Michael Lynch
Dardanelle, AR





--
Dennis Tillman W7pF
TekScopes Moderator

TM504 Front Panels

 

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Mlynch001
Sent: Tuesday, June 02, 2020 4:35 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

Harvey,

Modeling is not going to be an issue, just a matter of the time it will take to create the model. Those more complex front panels would be time consuming. I am not at all adverse to spending the time to do this project, but I would like to have samples of the panels so that I can produce an accurate model the first time.

It is possible to use the slicer program to position the model in whatever position makes best sense. Some slicers even do analysis of the model and position the model in the best orientation for printing. I’m going to work on that simple piece that Dennis is describing first of all. I knew that one of these plug ins had a simple front panel.

I will print these in PETG, since my machines are already calibrated for that material and that will yield a usable part immediately. I am not too fond of PLA, except in applications where durability is not an issue. PLA is extremely brittle and most of it does not hold up well in higher temps.

I have a light grey PETG that might look pretty good for these parts.

Appreciate your comments and ideas going forward.

Sincerely,


--
Michael Lynch
Dardanelle, AR





--
Dennis Tillman W7pF
TekScopes Moderator

TM 500 Front Panels

 

I forwarded your reply to the more appropriate topic subject line I started.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Harvey White
Sent: Tuesday, June 02, 2020 2:16 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

There are some things to consider when doing a 3D design that complicate the project, and for that matter, may or may not render the design "workable".

There has to be at least one flat space that hits the build platform. Modeling a cube standing on a point isn't a good idea.

There's a limit to how much and how long an overhang can be without having a support. Supports can be removed, if done gracefully. Otherwise, the unsupported part tends to sag.

If you use OpenSCAD, then it's a parametric modeler. You can easily specify the basic backplate and the edge as a model. You can base models off this. Adding a hole at a particular point, square or round, is easy. it takes a few lines of code.

Adding a boss on the front, or on the rear, is easy enough, however anything on the rear keeps the back from being flat, and that's a problem.

For material, PLA would be the material of choice to make the initial models. Making them out of ABS or PETG would be a good choice for durability.

Color is not going to be a problem, you can get pretty close.

There are ways of working around some of this, but those ways do make life more difficult.

Harvey


On 6/2/2020 4:50 PM, Dennis Tillman W7pF wrote:
There are no protrusions on the backside but the inner flat rectangular center of the front panel is recessed on the other side just like the front side. In other words the front panel is reversible.
It may not be necessary to recess it on the back side to make the design simpler.
On the front it would be highly desirable to have a small hole on every panel for the pull tab to go through.
I found a blank I can send you.

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of
Michael W. Lynch via groups.io
Sent: Tuesday, June 02, 2020 6:48 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

Dennis,

I am going to take a closer look at some of my TM500 plug ins and see if I can come up with a rough model. Sounds simple enough, as long as the back side of the blank is flat (there are no protrusions). Anything protruding would make the job more difficult. It may seem silly, but one of the most challenging tasks will be to get that thin outer rim of the blank to print properly. Thin sections such as that are problematic. This is where experimentation comes into play.

Another part of the project would be printing a Drill Jig to hold the two parts in perfect alignment, allowing drilling the various holes, so an exact match is achieved.

One of the nice things about 3D printing is that the operator can choose a wide variety of materials to build the model. I tend to use PETG, since the material is easy to print, solvent resistant and is not too brittle. ABS and Nylon are also options. Once the model is done, it is a simple matter to print in whatever color and type material that you wish.

I'm working on a set of cord wrap feet for my "new" 453, once those are complete, I will get on this project. I will let you know what I come up with.

Thanks for the inspiration.




--
Dennis Tillman W7pF
TekScopes Moderator

TOPIC CHANGE: TM500 Front Panels; WAS Advice about buying a 7904

 

This has changed into a discussion of TM500 front panels so it was time to change the topic.

Michael:
Contact me off list with your address and I will send you a blank panel
Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dennis Tillman W7pF
Sent: Tuesday, June 02, 2020 1:50 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

There are no protrusions on the backside but the inner flat rectangular center of the front panel is recessed on the other side just like the front side. In other words the front panel is reversible.
It may not be necessary to recess it on the back side to make the design simpler.
On the front it would be highly desirable to have a small hole on every panel for the pull tab to go through.
I found a blank I can send you.

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Michael W. Lynch via groups.io
Sent: Tuesday, June 02, 2020 6:48 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

Dennis,

I am going to take a closer look at some of my TM500 plug ins and see if I can come up with a rough model. Sounds simple enough, as long as the back side of the blank is flat (there are no protrusions). Anything protruding would make the job more difficult. It may seem silly, but one of the most challenging tasks will be to get that thin outer rim of the blank to print properly. Thin sections such as that are problematic. This is where experimentation comes into play.

Another part of the project would be printing a Drill Jig to hold the two parts in perfect alignment, allowing drilling the various holes, so an exact match is achieved.

One of the nice things about 3D printing is that the operator can choose a wide variety of materials to build the model. I tend to use PETG, since the material is easy to print, solvent resistant and is not too brittle. ABS and Nylon are also options. Once the model is done, it is a simple matter to print in whatever color and type material that you wish.

I'm working on a set of cord wrap feet for my "new" 453, once those are complete, I will get on this project. I will let you know what I come up with.

Thanks for the inspiration.

--
Michael Lynch
Dardanelle, Arkansas





--
Dennis Tillman W7pF
TekScopes Moderator





--
Dennis Tillman W7pF
TekScopes Moderator

Re: looking for 5500 uf cap for tek 475

 

It is only an 85°C cap that is already 17 years old.

On 6/2/2020 7:10 PM, Craig Cramb wrote:
tek part number 290-0584-00 . anybody have any to sell?
Ebay listing: 133209786060

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

Re: Advice about buying a 7904

Mlynch001
 

Dennis wrote:
It may not be necessary to recess it on the back side to make the design simpler.
On the front it would be highly desirable to have a small hole on every panel for the pull tab to go through.
I found a blank I can send you
Dennis,

Please do send it to me. I will get this designed and print a prototype. I will make sure that you get your sample back after the design phase is completed.

I can provide a rectangular hole for the pull tab and also any other holes that would be present on ALL versions of plug ins. I believe that there are some holes that must be common to all versions. Possibly the 4 screws that hold the front panel to the upper and lower aluminum extrusions?

Looking forward to getting this part designed and printed.

Thanks!

--
Michael Lynch
Dardanelle, AR

Re: Advice about buying a 7904

Mlynch001
 

Harvey,

Modeling is not going to be an issue, just a matter of the time it will take to create the model. Those more complex front panels would be time consuming. I am not at all adverse to spending the time to do this project, but I would like to have samples of the panels so that I can produce an accurate model the first time.

It is possible to use the slicer program to position the model in whatever position makes best sense. Some slicers even do analysis of the model and position the model in the best orientation for printing. I’m going to work on that simple piece that Dennis is describing first of all. I knew that one of these plug ins had a simple front panel.

I will print these in PETG, since my machines are already calibrated for that material and that will yield a usable part immediately. I am not too fond of PLA, except in applications where durability is not an issue. PLA is extremely brittle and most of it does not hold up well in higher temps.

I have a light grey PETG that might look pretty good for these parts.

Appreciate your comments and ideas going forward.

Sincerely,


--
Michael Lynch
Dardanelle, AR

Re: Oscilloscope Sales

Reed Dickinson
 

Hi Dave:
Planes have been known to fly dreamers to Southern California.  Maybe BCNU!
Reed

On Tuesday, June 2, 2020, 05:50:53 AM PDT, David Slipper <softfoot@...> wrote:

It's a shame you aren't in the UK - I'd be very tempted.
I can but dream.

Sigh,
Dave

Greetings fellow Tekkies:
In a few days I will be 86 years young and I feel the limits of age
slowly creeping through my joints.  Years ago I bid on a number of
Tektronix Oscilloscopes offered by the now defunct Hughes Corporation
here in Southern California.  My bid was high and when I went to pick
them up I found that what I got was about four times what I bid on. 
In the final result I came home three times with a pickup full of 465,
465B, 468, 475, 475A, 485 and three 7854 scopes.  The total was near
200.  I was the winning bidder and the workers loading the instruments
were more than glad to get rid of the scopes.  I now want to get my
garage back so I am offering these scopes first to members of this
forum.  After a few weeks on the forum I intend to put them on
Craigslist and after that on eBay.  I am not yet willing to sell the
485's but the other ones are game to be sold.
I also have a selection of plug-ins for the 7000 series of scopes at
$75 each or three for $200 or five for $300.
I am asking $100 for each oscilloscope, as-is, or three for $250. All
sales will be cash only.  I am not prepared to ship them so it will be
first-come-first-sold on a pickup only basis.  These scopes have not
been canibalized for parts and are just like I got them years ago.
I would be open for reasonable bids on any quantity of these scopes.
For more information please email me at reed714@... or write
me at:
Reed Dickinson1705 Stonehenge DriveTustin, CA  92780
714.838.6241 (please call afternoons only)



.

Re: looking for 5500 uf cap for tek 475

Craig Cramb
 

tek part number 290-0584-00 . anybody have any to sell?
Ebay listing: 133209786060

Re: Advice about buying a 7904

Harvey White
 

There are some things to consider when doing a 3D design that complicate the project, and for that matter, may or may not render the design "workable".

There has to be at least one flat space that hits the build platform.  Modeling a cube standing on a point isn't a good idea.

There's a limit to how much and how long an overhang can be without having a support.  Supports can be removed, if done gracefully.  Otherwise, the unsupported part tends to sag.

If you use OpenSCAD, then it's a parametric modeler.  You can easily specify the basic backplate and the edge as a model.  You can base models off this.  Adding a hole at a particular point, square or round, is easy.  it takes a few lines of code.

Adding a boss on the front, or on the rear, is easy enough, however anything on the rear keeps the back from being flat, and that's a problem.

For material, PLA would be the material of choice to make the initial models.  Making them out of ABS or PETG would be a good choice for durability.

Color is not going to be a problem, you can get pretty close.

There are ways of working around some of this, but those ways do make life more difficult.

Harvey

On 6/2/2020 4:50 PM, Dennis Tillman W7pF wrote:
There are no protrusions on the backside but the inner flat rectangular center of the front panel is recessed on the other side just like the front side. In other words the front panel is reversible.
It may not be necessary to recess it on the back side to make the design simpler.
On the front it would be highly desirable to have a small hole on every panel for the pull tab to go through.
I found a blank I can send you.

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Michael W. Lynch via groups.io
Sent: Tuesday, June 02, 2020 6:48 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

Dennis,

I am going to take a closer look at some of my TM500 plug ins and see if I can come up with a rough model. Sounds simple enough, as long as the back side of the blank is flat (there are no protrusions). Anything protruding would make the job more difficult. It may seem silly, but one of the most challenging tasks will be to get that thin outer rim of the blank to print properly. Thin sections such as that are problematic. This is where experimentation comes into play.

Another part of the project would be printing a Drill Jig to hold the two parts in perfect alignment, allowing drilling the various holes, so an exact match is achieved.

One of the nice things about 3D printing is that the operator can choose a wide variety of materials to build the model. I tend to use PETG, since the material is easy to print, solvent resistant and is not too brittle. ABS and Nylon are also options. Once the model is done, it is a simple matter to print in whatever color and type material that you wish.

I'm working on a set of cord wrap feet for my "new" 453, once those are complete, I will get on this project. I will let you know what I come up with.

Thanks for the inspiration.

Re: SC502 Old Enough to Smoke?

Larry McDavid
 

The Tek SC502 full manual is available on the TekWiki website here:

http://w140.com/tekwiki/wiki/SC502

I have a SC502 that works ok. I also have a SC504 that works ok.

Larry

On 6/2/2020 12:40 PM, DaveH52 wrote:
I have a TM506 that came with a full load of plugins, all of which seem to work OK except the SC502 which emits a magic smoke smell. My uncalibrated nose tells me it's coming from the A1 main board on the bottom. My uncalibrated eyes did not detect anything looking discolored or burnt just an old spider nest that has since been removed. My uncalibrated nose says it's not coming from the HV supply section. Are there any "usual suspects" I should investigate first, before applying power again?
--
Best wishes,

Larry McDavid W6FUB
Anaheim, California (SE of Los Angeles, near Disneyland)

Re: SC502 Old Enough to Smoke?

 

Hi Dave,
Tantalum caps are the most obvious culprit. They usually have a small value (10 ohms for example) resistors in series with them. When the tantalum shorts the resistor overheats and disintegrated into a little black cylinder. Sometimes the area around the resistor is black too. Most of the time these tantalums are near the connectors on the rear where power comes into the plugin. The burned up resistors are a good thing to look for and usually easy to spot.

Next thing to do is check each tantalum capacitor for a short by putting an ohmmeter across it

Dennis Tillman W7pF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Dave Daniel
Sent: Tuesday, June 02, 2020 12:50 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] SC502 Old Enough to Smoke?

Is the ‘scope working to spec?

On Jun 2, 2020, at 15:40, DaveH52 <@DaveH52> wrote:

I have a TM506 that came with a full load of plugins, all of which seem to work OK except the SC502 which emits a magic smoke smell. My uncalibrated nose tells me it's coming from the A1 main board on the bottom. My uncalibrated eyes did not detect anything looking discolored or burnt just an old spider nest that has since been removed. My uncalibrated nose says it's not coming from the HV supply section. Are there any "usual suspects" I should investigate first, before applying power again?






--
Dennis Tillman W7pF
TekScopes Moderator

Re: SC502 Old Enough to Smoke?

DaveH52
 

No, it seems to be completely dead. I'm currently trying to locate the +/-20V and 5V test points to seem if one of them is overloaded.

Re: Oscilloscope Sales

 

Please contact Reed off list.

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Abc Xyz
Sent: Tuesday, June 02, 2020 11:25 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Oscilloscope Sales

Reed,

I am in Southern California also and have been trying to Repair a 465 and a 465B. It sure would be helpful if you had a Working Unit to use for Comparison Readings.

JR

On Tue, Jun 2, 2020, 2:29 AM Reed Dickinson <reed714@...> wrote:


Greetings fellow Tekkies:
In a few days I will be 86 years young and I feel the limits of age
slowly creeping through my joints. Years ago I bid on a number of
Tektronix Oscilloscopes offered by the now defunct Hughes Corporation
here in Southern California. My bid was high and when I went to pick
them up I found that what I got was about four times what I bid on.
In the final result I came home three times with a pickup full of 465,
465B, 468, 475, 475A, 485 and three 7854 scopes. The total was near
200. I was the winning bidder and the workers loading the instruments
were more than glad to get rid of the scopes. I now want to get my
garage back so I am offering these scopes first to members of this
forum. After a few weeks on the forum I intend to put them on
Craigslist and after that on eBay. I am not yet willing to sell the 485's but the other ones are game to be sold.
I also have a selection of plug-ins for the 7000 series of scopes at
$75 each or three for $200 or five for $300.
I am asking $100 for each oscilloscope, as-is, or three for $250. All
sales will be cash only. I am not prepared to ship them so it will be
first-come-first-sold on a pickup only basis. These scopes have not
been canibalized for parts and are just like I got them years ago.
I would be open for reasonable bids on any quantity of these scopes.
For more information please email me at reed714@... or write
me
at:
Reed Dickinson1705 Stonehenge DriveTustin, CA 92780
714.838.6241 (please call afternoons only)







--
Dennis Tillman W7pF
TekScopes Moderator

Re: Advice about buying a 7904

 

Hi Michael,
You are correct. Those plugins and many of the newer "A" versions of the DM5xxA models have a more complex front panel.
But the plugins with complicated 3D extruded front panels make up less than 10% of what was made.
A blank front panel with the front area recessed (and a flat backside) will make it possible to restore the appearance of a lot of otherwise perfectly working plugins with damaged front panels
Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Michael W. Lynch via groups.io
Sent: Tuesday, June 02, 2020 7:38 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

Dennis,

Taking a very cursory look at a few TM500 plug ins, I see some issues here, For example, my PG506 and DM502A (surely others as well?) have a very complex back plane with mounting bosses as well as screws that come in from the sides, with threaded inserts. In themselves, These are not insurmountable, however, it does make for a much more complex 3D printing problem, mainly because of the dimensional accuracy required for proper alignment of all the parts. Later design Plug ins are not flat on the front or the back sides e.g. there are recesses and/or protrusions on both sides.

Perhaps there are some that are less complex that you could suggest that would be better candidates??

I am not going to abandon the idea, but it will take some time to figure out the best way to approach the problem .

--
Michael Lynch
Dardanelle, Arkansas





--
Dennis Tillman W7pF
TekScopes Moderator

Re: looking for 5500 uf cap for tek 475

Eric
 

Graham try Oshpark direct from the PCB maker. 11 us for 3 adapters.  At least it was not sure what the shipping would be.

On 6/2/2020 10:44 AM, VK1GVC wrote:
Jeff, I see you've found them on fleabay but FYI Michael posted about 10 days ago that they were eBay item 273254508468 where I found them too.  The cost of a set of boards is USD11 whereas the postage to AUS is about USD19 - hardly a good deal unfortunately.  I asked the seller about any less costly postage and he said he was bound by eBay rules to have package tracking, hence the cost.  I guess I'll do without.

Hope your postage costs within CONUS are a bit more reasonable!

Graham

On 3/06/2020 12:14 am, jeff corey wrote:
Wow, thanks to all for your prompt responses!  I found the adapter boards on fleebay and will order some and re-cap the 5 caps in the PS with newer technology.  I have been away from my roots as a EE  running a sucessfull IT company that pays more, but with quarantine and all i have had more time and interest in repairing old equipment.  Component technology has sure changed since the big can capacitors we designed into the 48 v power suplies at the ITT phone company where I started.  I remember a tech soldered one in backwards and I was up on a ladder debugging some wirewarap backplanes and it narrowly missed my ear as it shot its outer can off like a bullet.

Of course now that I have gotten reinterested in boat anchor tech the Hamfests are a distant memory.  Hope they can start up again!

Jeff  WB9KAZ


Re: Advice about buying a 7904

 

There are no protrusions on the backside but the inner flat rectangular center of the front panel is recessed on the other side just like the front side. In other words the front panel is reversible.
It may not be necessary to recess it on the back side to make the design simpler.
On the front it would be highly desirable to have a small hole on every panel for the pull tab to go through.
I found a blank I can send you.

Dennis

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Michael W. Lynch via groups.io
Sent: Tuesday, June 02, 2020 6:48 AM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Advice about buying a 7904

Dennis,

I am going to take a closer look at some of my TM500 plug ins and see if I can come up with a rough model. Sounds simple enough, as long as the back side of the blank is flat (there are no protrusions). Anything protruding would make the job more difficult. It may seem silly, but one of the most challenging tasks will be to get that thin outer rim of the blank to print properly. Thin sections such as that are problematic. This is where experimentation comes into play.

Another part of the project would be printing a Drill Jig to hold the two parts in perfect alignment, allowing drilling the various holes, so an exact match is achieved.

One of the nice things about 3D printing is that the operator can choose a wide variety of materials to build the model. I tend to use PETG, since the material is easy to print, solvent resistant and is not too brittle. ABS and Nylon are also options. Once the model is done, it is a simple matter to print in whatever color and type material that you wish.

I'm working on a set of cord wrap feet for my "new" 453, once those are complete, I will get on this project. I will let you know what I come up with.

Thanks for the inspiration.

--
Michael Lynch
Dardanelle, Arkansas





--
Dennis Tillman W7pF
TekScopes Moderator

Re: SC502 Old Enough to Smoke?

Dave Daniel
 

Is the ‘scope working to spec?

On Jun 2, 2020, at 15:40, DaveH52 <@DaveH52> wrote:

I have a TM506 that came with a full load of plugins, all of which seem to work OK except the SC502 which emits a magic smoke smell. My uncalibrated nose tells me it's coming from the A1 main board on the bottom. My uncalibrated eyes did not detect anything looking discolored or burnt just an old spider nest that has since been removed. My uncalibrated nose says it's not coming from the HV supply section. Are there any "usual suspects" I should investigate first, before applying power again?


SC502 Old Enough to Smoke?

DaveH52
 

I have a TM506 that came with a full load of plugins, all of which seem to work OK except the SC502 which emits a magic smoke smell. My uncalibrated nose tells me it's coming from the A1 main board on the bottom. My uncalibrated eyes did not detect anything looking discolored or burnt just an old spider nest that has since been removed. My uncalibrated nose says it's not coming from the HV supply section. Are there any "usual suspects" I should investigate first, before applying power again?