Tektronix 2465B oscilloscope teardown

[SoundTech-LG]

So it may be a "feature" of 2467B's...  nice...   Come to think of it, I don't remember my 2465B exhibiting the flicker, but both 2467Bs certainly do it, and it IS annoying.

[AMR Labs]

I have an 2467B that has that slight flickering of the intensity as well...
Recap already done, all voltages rock steady, but still.
Must be something with these MCP intensity amplifier CRT's.

Haven't had access to a 2467 type scope yet, so no idea how the flickering looks like,  but if possible a short video would document that flicker nicely for future references. I wonder what the experts over at Tekgroup-io would have to say about it, normal or not?

[factory]

Also going to have a look at the IEC filter at the weekend, forgot to photo it. 

Almost forgot about this, the mid 1980's 2465 I'm currently working on has a Japanese made TDK IEC filter module, has anyone had any problems with this type?

Two of the slightly newer scopes here, a 2445A & 2465B (later 1980's) have a Swiss made Schaffner IEC filter module, these are known to fail in the same way as the infamous RIFA paper filter capacitors do, we had one release the smoke at work (in a Cropico ohm meter), I don't ever want the smell of another one of those stink bombs failing again. 



David

[WastelandTek]

I apologize again for messing up this thread with somewhat off topic questions.  I am always fearful when I actually post on this forum that I will demonstrate myself to be painfully ignorant. 

It is 6 months later and I am finally getting around to actually ordering parts for my vanilla 2445, in particular to address the RAM issue.
There is a fair bit of information around on various models.  David piped up a few pages ago with the parts used in his 2440, and I get Google hits on the 2445A and 2445B, both of which also seem to use the Dallas NVRAM parts.

However, it appears that the 2445 (no A or B) uses an ER1400 EAROM instead.  There is a thread from 2013 here that suggests a replacement part as M5G1400P, they can be had, but I don't know if it is even safe to desolder this thing?
Any ideas guys?

[AMR Labs]

...

However, it appears that the 2445 (no A or B) use an ER1400 EAROM instead.  There is a thread from 2013 here that suggests a replacement part as M5G1400P, they can be had, but I don't know if it is even safe to desolder this thing?
Any ideas guys?

It is my understanding the the plain models (no A or B suffix) do not require a replacement of the RAM chip (unless defective), as these older models do not use a NVRAM chip but rather they rely on a completely separate on-board external battery as backup, instead of the battery being hidden inside the same RAM chip. So in this case the battery replacement is a much simpler procedure and the only thing to keep in mind is to provide a temporary 3V supply to the board while the old battery is being extracted and the new one is soldered in. Usually you can do that by joining two AA cells in series and connect this in parallel with the existing old battery with a couple of short wires to keep the memory contents alive during the surgery.

[Satbeginner]

Hi, I have a 2465 with a through hole A5 pcb, that one has a ER1400 chip. I found a replacement, but in the end it was not broken. Just an incomplete calibration caused the dots to show.

My 2464A has a battery backed up memory on a through hole pcb, and my 2465B and 2467B ( both and A5 SMD PCBs) have a Dallas chip.

So, there are three versions of the A5, where the battery backuped versions exist in two versions again.

ER1400, 2* Battery backup, Dallas

Un saludo,

Leo

[tggzzz]

However, it appears that the 2445 (no A or B) uses an ER1400 EAROM instead.  There is a thread from 2013 here that suggests a replacement part as M5G1400P, they can be had, but I don't know if it is even safe to desolder this thing?
Any ideas guys?

I have no comment about that specific IC.

Unless you have the equipment to be able to do a full calibration, the problem would be getting the calibration coefficients out of the existing ROM and inserting them into the new ROM. Getting them out can be done using the test sequence and writing down what you see on the screen.

[med6753]

It's basically broken down as follows:

2445/2465 (No suffix): Pin thru hole A5 board. The EAROM does not have, nor does it require, a battery backup.

2445A/2465A: Pin thru hold A5 board. Don't recall chip type but it does have an external battery soldered to the A5 board.

2445B/2465B: SMT A5 board. Has the Dallas chip with internal battery.

Now supposedly some 2445A/2465A also have the SMT A5 board but not sure. 

[emece67]

.

[WastelandTek]

It's basically broken down as follows:

2445/2465 (No suffix): Pin thru hole A5 board. The EAROM does not have, nor does it require, a battery backup.

snip

Thank you.  This seems to be the case as I can locate no battery on my A5 and a search for the word "battery" in the service manual reveals no hits.

I guess manually recording the cal data just in case and some caps and I am "safe" to keep using this thing.

One other wrinkle you folks are probably aware of but I will throw in for the benefit of anyone searching in the future; common EPROM programmers do not supply the -30V necessary to program EAROMs...so there's that...

[med6753]

It's basically broken down as follows:

2445/2465 (No suffix): Pin thru hole A5 board. The EAROM does not have, nor does it require, a battery backup.

2445A/2465A: Pin thru hold A5 board. Don't recall chip type but it does have an external battery soldered to the A5 board.

2445B/2465B: SMT A5 board. Has the Dallas chip with internal battery.

Now supposedly some 2445A/2465A also have the SMT A5 board but not sure.

I do have a 2465B with the THT A5 board and the Li/SOCl2 cell soldered on it.

OK, apparently I had at backwards. I guess some early 2445B/2465B's had a pin thru hole A5 board.

[LADmachining]

It's basically broken down as follows:

2445/2465 (No suffix): Pin thru hole A5 board. The EAROM does not have, nor does it require, a battery backup.

2445A/2465A: Pin thru hold A5 board. Don't recall chip type but it does have an external battery soldered to the A5 board.

2445B/2465B: SMT A5 board. Has the Dallas chip with internal battery.

Now supposedly some 2445A/2465A also have the SMT A5 board but not sure.

My 2445B has a through-hole board.  The memory IC is an NEC D4364C-15LL

[Bud]

Heck, that made me google for Guernsey channel islands 

[AMR Labs]

My 2445B has a through-hole board.  The memory IC is an NEC D4364C-15LL

Your "Keeper"  battery seems to have a 1990 date code, perhaps its time to replace it.

[WastelandTek]

well this is stupid

I can't seem to find suitable axial caps anywhere to replace the 290uF 200V units in the fan motor plastic on A3.

You would think that 330uF 250V would be the modern one...Digikey lists 2, both non stock with minimums in the tens...

Mouser has none

RFParts is showing 470uF 200V axials in stock...but that seems like a lot of extra cap...do I just buy radials and fold the lead over and extend it??  seems...inelegant.

[med6753]

well this is stupid

I can't seem to find suitable axial caps anywhere to replace the 290uF 200V units in the fan motor plastic on A3.

You would think that 330uF 250V would be the modern one...Digikey lists 2, both non stock with minimums in the tens...

Mouser has none

RFParts is showing 470uF 200V axials in stock...but that seems like a lot of extra cap...do I just buy radials and fold the lead over and extend it??  seems...inelegant.

Had the same issue. Yep, bought the radials and folded the lead and extended it.

[tautech]

well this is stupid

I can't seem to find suitable axial caps anywhere to replace the 290uF 200V units in the fan motor plastic on A3.

Plenty to choose from here:
https://www.tedss.com/Capacitors/Browse/aluminum-electrolytic-axial

[WastelandTek]

Plenty to choose from here:
https://www.tedss.com/Capacitors/Browse/aluminum-electrolytic-axial

That is a neat site that I was not aware of, but the only 330uF 250V axial I'm seeing is 3" long 

looks like long leads and elegance be dammed...

[tautech]

well this is stupid

I can't seem to find suitable axial caps anywhere to replace the 290uF 200V units in the fan motor plastic on A3.

Plenty to choose from here:
https://www.tedss.com/Capacitors/Browse/aluminum-electrolytic-axial

That is a neat site that I was not aware of, but the only 330uF 250V axial I'm seeing is 3" long 

Try this one:
https://www.tedss.com/2020058128

[WastelandTek]

hmmmmmmmm

even better  https://www.tedss.com/2020058049

like they were made for it, I wonder how old this stock is though


editing to add these useful links for easy finding

http://www.kerrywong.com/2013/04/25/tektronix-2445-teardown/

http://www.kerrywong.com/2016/02/22/teardown-of-a-tektronix-2465/

http://www.condoraudio.com/wp-content/uploads/Projects/Tektronix-2465B-Oscilloscope-Restoration-Repair.pdf

https://antiqueradios.com/forums/viewtopic.php?f=8&t=235478

[LADmachining]

My 2445B has a through-hole board.  The memory IC is an NEC D4364C-15LL

Your "Keeper"  battery seems to have a 1990 date code, perhaps its time to replace it.

Well spotted!  This photo was taken before I exchanged the battery - it was replaced shortly after.

Anthony

[AMR Labs]

My 2445B has a through-hole board.  The memory IC is an NEC D4364C-15LL

Your "Keeper"  battery seems to have a 1990 date code, perhaps its time to replace it.

Well spotted!  This photo was taken before I exchanged the battery - it was replaced shortly after.

Anthony

 

[WastelandTek]

so guys

I am just about to reassembly on my vanilla 2445 after a full recap and I wanted to show off my custom U800 heatsink solution.  I'm pretty proud of it.

It seems pretty clear to me that Tektronix, at some point in the design process, contemplated a heatsink here given the mounting screws they included.  So I tried to make something close to what I imagined they had in mind.

[Electro Fan]

so guys

I am just about to reassembly on my vanilla 2445 after a full recap and I wanted to show off my custom U800 heatsink solution.  I'm pretty proud of it.

It seems pretty clear to me that Tektronix, at some point in the design process, contemplated a heatsink here given the mounting screws they included.  So I tried to make something close to what I imagined they had in mind.




was

That looks pretty cool, and it’s very neat to think about and maybe actually extend/improve upon whatever Tektronix might have contemplated. (And gregarious is great too.) Thanks for sharing.

[med6753]

I don't want to fire up the debate concerning heatsinking U800 again...which has been discussed ad nauseum in this thread....but IMHO an additional heat sink, especially on a Tek die U800, is completely unnecessary if the cooling system in the scope is properly maintained.