Test Equipment Anonymous (TEA) group therapy thread

[Housedad]

Xrunner -  When I saw the pic of those fuse clips, they looked so familiar to me but I just could not place them in my memories for a while.  Now, after looking at a couple thousand Google images, it hit me.  Those type of clips used to be in some Radio shack equipment that I owned way back when.  BUT they were in a plastic fuse holder!  I re-ran through a billion more pics and I saw a few here and there that have those clips inside the block.  They are in the cheap blocks.  I wonder if the person that used that unit got sick and tired of pulling the fuses out of the block and just pulled the clips out and soldered them back on the board.  Since so many fuses were blown on the board, it may be that they blew the fuses often enough to make the change so it would be easier to replace them.

An example:

http://www.chonelectronics.com/product/fuse-holder-cover-5x20mm-m205-pcb-4a/

[xrunner]

Still a crying shame those lovely old fuse holders were busted, got any donor units ?
I'd be looking for some NOS real 1/4" fuses. 

I do have a donor - another TM504.

I got it because I wanted the original green connector (and perhaps other parts) to fix the really nice TM504 I got with the damaged connector. The donor was only $40. But since another basically identical connector was found, I can use the spare fuse holders in that one to make the better one original.

The other TM504 isn't in that bad a shape though. It looked really rough in the buyer's pic, but it cleaned up pretty nicely. All the screws that hold the top cover on were stripped out, but I've since re-tapped them to the next larger screw (8x32). It also had an issue with the power switch rail, but that was just bent and was easy to fix. So, I can replace the scavenged fuse holders from it (which were only holding the spare fuses) with the next best thing that Housedad found. It's all good ... 

This forum is such a good resource - I can only hope that I give back as much as I take away.

[xrunner]

Xrunner -  When I saw the pic of those fuse clips, they looked so familiar to me but I just could not place them in my memories for a while.  Now, after looking at a couple thousand Google images, it hit me.  Those type of clips used to be in some Radio shack equipment that I owned way back when.  BUT they were in a plastic fuse holder!

HA! Pretty good, they are close except for one thing - the bottom of the Tek ones have two small pins. But not bad.

I wonder if the person that used that unit got sick and tired of pulling the fuses out of the block and just pulled the clips out and soldered them back on the board.  Since so many fuses were blown on the board, it may be that they blew the fuses often enough to make the change so it would be easier to replace them.

No, they are all original. I have two units that are all the same. Original vintage parts. 

[tautech]

Still a crying shame those lovely old fuse holders were busted, got any donor units ?
I'd be looking for some NOS real 1/4" fuses. 

I do have a donor - another TM504.

I got it because I wanted the original green connector (and perhaps other parts) to fix the really nice TM504 I got with the damaged connector. The donor was only $40. But since another basically identical connector was found, I can use the spare fuse holders in that one to make the better one original.

The other TM504 isn't in that bad a shape though. It looked really rough in the buyer's pic, but it cleaned up pretty nicely. All the screws that hold the top cover on were stripped out, but I've since re-tapped them to the next larger screw (8x32). It also had an issue with the power switch rail, but that was just bent and was easy to fix. So, I can replace the scavenged fuse holders from it (which were only holding the spare fuses) with the next best thing that Housedad found. It's all good ... 

This forum is such a good resource - I can only hope that I give back as much as I take away.

Easy to pay back IMO with our collect knowledge and wisdom.
We help each other and those that find our posts when we aren't around anymore.
There's a few that sadly cease posting  and we can only be thankful for that they contributed before they stop.

A bit of a look through the members list is a grim reminder of our short time here. 

[bitseeker]

Added "Bait Theory" to the Glossary.

[xrunner]

The first of three more plug-ins arrived today - a DM502. It's in pretty damn good condition too. If anyone hasn't seen inside one, the main function switch is interesting. It's a long plastic tube with cams. The DC504 had the same type of switch only smaller. The switches are on the PCB underneath it. As you turn it the cams close the appropriate switches. What a fun job designing that cam must have been!

Oh, and inside we have the same fuse holders that they used in the TM504 chassis.

[Cubdriver]

Added "Bait Theory" to the Glossary.

It worked for me with the 3450A DVM.  I spotted a manual on the 'bay and grabbed it, then a few months later stumbled upon a meter.   

-Pat

[tautech]

The first of three more plug-ins arrived today - a DM502. It's in pretty damn good condition too. If anyone hasn't seen inside one, the main function switch is interesting. It's a long plastic tube with cams. The DC504 had the same type of switch only smaller. The switches are on the PCB underneath it. As you turn it the cams close the appropriate switches. What a fun job designing that cam must have been!

That does look very clean. Nice.

Oh, and inside we have the same fuse holders that they used in the TM504 chassis.

Complete with proper 1/4" fuses. 

[xrunner]

Tautech - you got those Siglent complainers under control yet? 

[tautech]

Tautech - you got those Siglent complainers under control yet? 

They're always be some, a fast growing company get's some notice taken of it and especially when they start challenging/competing with existing brands and models. Never a dull moment as all manner of things are going on, but that seems the way of the industry these days, more brands, more competition, more innovation and the best bit.........more choices for buyers. 

Hell I wish it was like this when I was a boy. 

[AF6LJ]

Added "Bait Theory" to the Glossary.

It worked for me with the 3450A DVM.  I spotted a manual on the 'bay and grabbed it, then a few months later stumbled upon a meter.   

-Pat

I am going to have to try that.

[bitseeker]

The first of three more plug-ins arrived today - a DM502. It's in pretty damn good condition too. If anyone hasn't seen inside one, the main function switch is interesting. It's a long plastic tube with cams. The DC504 had the same type of switch only smaller. The switches are on the PCB underneath it. As you turn it the cams close the appropriate switches. What a fun job designing that cam must have been!

Wow, what a monster switch. I guess there were too many positions for a more typical rotary one?

[xrunner]

Wow, what a monster switch. I guess there were too many positions for a more typical rotary one?

Hmmm ... not sure why. The DM501A had push buttons, which were also stacked. Seemed like a lot of mechanicalness for a little DMM. This seems a lot simpler except for the upfront design of that long cam. Just switches on a PCB - no springs and such. I guess it works!

So I now want to go through the cal on the DM502. You can see how the extender cable is nice. The second step in the cal is actually checking the DMM's clock.  Yep, you gotta adjust that clock for a frequency of 20.48 kHz +/-0.2 kHz. I am in deep trouble here, it's a wonder the thing is even working because the clock is 20.044 kHz! I hope I can adjust it properly. It's even being generated by a 555 timer. You gotta love it!

[bitseeker]

A 555? Nifty. Infinitely adjustable!

[xrunner]

A 555? Nifty. Infinitely adjustable!

Overclock a DMM? 

Well I got the FG501A. I verified it does not have an output as the seller said. I initially was betting on the output stage being blown - but ...

I think I'll start a repair thread on it, because I've already started down the rabbit hole - I do not know what is wrong with it yet, but I do know what is right with it. It's looking interesting ... might be a useful thread for someone in the future. I'll post the link here later today. 

[xrunner]

Repair thread -

https://www.eevblog.com/forum/repair/repair-of-tektronix-fg501a-function-generator/

[iainwhite]

I scored an HP 3478A for $91 inc shipping - also a cheapo chinese voltage ref - I sense symptoms of volt-nut Lite . . . hopefully i can stop at 5.5 digits?

[Cubdriver]

I fear I'm going to become a Volt-Nut.  We have been cleaning out the back of the radio museum where I volunteer, and stumbled upon this little beauty that had been hiding there facing the wall for lord only knows how many years.  I've given it a new home.   

Fluke 7105A Calibration System:



Other than some sticker residue it appears to be in excellent shape.  Its operational status remains to be determined.

(Now to pull everything from the rack so I can get it out of the Jeep and into the house...)
(Oh, and find manuals so I can learn to drive it...)

-Pat

[mtdoc]

Cubdriver, as Dave would say "Beauty!"

[AF6LJ]

I fear I'm going to become a Volt-Nut.  We have been cleaning out the back of the radio museum where I volunteer, and stumbled upon this little beauty that had been hiding there facing the wall for lord only knows how many years.  I've given it a new home.   

Fluke 7105A Calibration System:



Other than some sticker residue it appears to be in excellent shape.  Its operational status remains to be determined.

(Now to pull everything from the rack so I can get it out of the Jeep and into the house...)
(Oh, and find manuals so I can learn to drive it...)

-Pat

Aren't you the lucky one Pat.

Cool...

[AF6LJ]

I scored an HP 3478A for $91 inc shipping - also a cheapo chinese voltage ref - I sense symptoms of volt-nut Lite . . . hopefully i can stop at 5.5 digits?

Everyone should have at least one 3478...

 

[xrunner]

I fear I'm going to become a Volt-Nut.  We have been cleaning out the back of the radio museum where I volunteer, and stumbled upon this little beauty that had been hiding there facing the wall for lord only knows how many years.  I've given it a new home.   

You lucky devil you. 

[xrunner]

I scored an HP 3478A for $91 inc shipping -

Nice meter, I have one myself.

I sense symptoms of volt-nut Lite . . . hopefully i can stop at 5.5 digits?

 

Ah - no.

[Cubdriver]

Indeed, I'm very happy with this score!  There are definitely some nice perqs to spending my Saturdays driving an hour from home to help out at the museum!!  (My floor joists, however, might not share that opinion.)  I've found scanned manuals on the Fluke site for the 335A, 845AR and 721A.  Nothing yet for the others, though admittedly I have not yet looked very hard, checking only Fluke, BAMA and K04BB thus far.  Perhaps Artek has scans; will look there if I can't find the actual hard copies (which I much prefer) for a reasonable cost on the 'bay.

The 720A sports a cal sticker; it was last done in October of 1984.  My guess is that this system was likely retired shortly after that.  I've gotten the pieces inside; will pop some covers and take a few photos shortly.

-Pat

[bitseeker]

I scored an HP 3478A for $91 inc shipping - also a cheapo chinese voltage ref - I sense symptoms of volt-nut Lite . . . hopefully i can stop at 5.5 digits?

Unlikely. Maybe at 6.5 digits.

Indeed, I'm very happy with this score!  There are definitely some nice perqs to spending my Saturdays driving an hour from home to help out at the museum!!

I should say so! Congrats on a whole system to get you started, Pat.