Date   

Re: 7854 Repair & Restoration

 

On 13 Mar 2016 19:42:25 -0700, you wrote:

It did not fix the problem. Hmmm.....

I'll go through the voltages around the vertical amp board tomorrow. I need to try and sleep off the rest of this sinus infection.

What do you think the chances are that U50 is going bad? I suppose it couldn't hurt to have a spare anyway... I can just buy one, swap it, and see.
I cannot say that it is impossible that U50 went bad causing the
problem but I hoped it was something else like a cracked solder joint
or open resistor.

Replacing U50 can certainly be done but I do not know that anybody
knows the tuning procedure for adjusting R43, R47, L133, L163, and any
other selected parts. Transient response adjustment will be tricky to
impossible without a 7000 standardizer and reference level tunnel
diode pulser but I think you can get close enough for practical
purposes.


Re: 7854 Repair & Restoration

 

On 13 Mar 2016 18:59:43 -0700, you wrote:

...

I think I've found the culprit. I forgot to photograph it before fixing it, though. On the rear of the board, there are a few components soldered to the sockets.
On Pin 8 of U50, R168 is soldered. There was almost no solder actually there, so after all the years of temperature changes around those connections, the solder cracked. I'm not 100% that it was the culprit since it could have still maintained a connection by some tiny amount of solder left holding, but it seems likely. It's on one side of that pot - R160 - that you said you had to replace.

Would this explain why the trace appeared to have deflected vertically off the screen?
If you mean R163 then no, an open there would not cause upward
vertical deflection. Instead it would cause a vertical gain increase
around the center line of the CRT.

I'm done reflowing the joints, the IPA has dried, and I'm going to put everything back together and confirm whether it's resolved or not.


Re: 7854 RAM card upgrade only - any interest?

 

On 13 Mar 2016 17:18:41 -0700, you wrote:

I agree. The C4xx series of caps are used as supply voltage bypass in almost all cases (on A25, A28, A31 and A36 at least). A3C430 is an anomaly.

You might be able to test by unplugging the ribbon cable on A3. It would disable the front keyboard and lights but not the external oKB, I think, and you could look at the waveforms again. Floating P108 pin 5 would be another way, but not easily done.

The LED drive lines on A3 are also decoupled by 0.1uf, but they are C1xx and C2xx so are probably not part of the same design decisions.
I am not sure why they decoupled the CRU outputs used to drive the
keyboard indicators at all.

C430 was installed at SN B010151 according to my manual, which may be only the 51st 7854 produced. I think it has been overlooked, in part because it is shown at the far end of the keyboard cable wiring and nothing other than C430 is on that line in the A3 diagram. In reality, the point to point wiring is not that way; the ribbon cable goes from the MPU top connector to the A3 board, and continues from there to the rear connector board.

The changes made at SN B010151 are a grab bag of minor parts value modifications, mostly resistors in power supply areas. None of the 8 affected circuit boards changed part number, so Tek apparently did not consider any of these changes mandatory. I don't think any of the changes were revisited after B010151.

Cliff
I suspect what happened is someone saw board A3 in isolation and
figured the decoupling capacitor for KBID got left out so they added
it without considering what KBID was really being used for.

Originally I wanted to remove A3C430 or lower its value but without
removing the A3 board, I do not think I can even identify it easily.
A3C430 is not shown on the board layout diagram and I did not find a
change notice for it.

If it can be considered a problem, then I have a better solution
anyway which will not require modifying anything; just add about 470
ohms in series with the collector of the transistor. That will limit
the short circuit current.


Re: 7854 Repair & Restoration

Brian Bloom
 

It did not fix the problem. Hmmm.....

I'll go through the voltages around the vertical amp board tomorrow. I need to try and sleep off the rest of this sinus infection.

What do you think the chances are that U50 is going bad? I suppose it couldn't hurt to have a spare anyway... I can just buy one, swap it, and see.


1502 failure

Peter Gottlieb
 

I have a working 1502 and one I had picked up cheap as a parts unit.

Neither printer worked. The printer in my working 1502 is the older type but the one that came with the parts 1502 is newer but had the disintegrated o-rings on the paper roller.

I wanted to see if the newer printer worked but it wouldn't connect to the 15 pin D connector. It seems the frame is a bit bent. I had made up an extension cable to debug the printer and when pushing it in something shorted. Batt V is always live on the printer pins! Turns out I blew the fuse on the battery. Replaced it and all I got was an unfocussed spot on the CRT. Investigation found no -5. The 2N2222A pass transistor was open, but the real fault was a shorted 160uF 6 Volt tantalum on the main board under the shield cover. Big orange dipped axial made by Sprague. Replaced it with a 10 Volt one. Put a new 2222A in but the 741 driving it was shot too, so replaced that and the unit is running again. I don't know if my shorting +B to ground did the damage or the tantalum just decided to die but whatever.

Next I'm going to put the best mechanical parts into the newer rev printer and replace any bad components.

There are a bunch of 6 volt tantalums on the 5 volt lines, perhaps I should replace all of them with higher voltage parts while I have it open.

Peter


Re: 7854 Repair & Restoration

Brian Bloom
 

Well I'm glad I've got assistance in sorting all of this out!

In addition to that, I've learned to take my time and think on it when it's an entirely new-to-me task. I made the mistake of rushing into a repair without doing proper research only to find out that nearly everything I did was totally unnecessary... that was my first repair scope and what I chose to use to learn about circuitry and troubleshooting with. Actually, it's the very same 468 that you helped me resolve the A/B sweep start offset on.


I think I've found the culprit. I forgot to photograph it before fixing it, though. On the rear of the board, there are a few components soldered to the sockets.
On Pin 8 of U50, R168 is soldered. There was almost no solder actually there, so after all the years of temperature changes around those connections, the solder cracked. I'm not 100% that it was the culprit since it could have still maintained a connection by some tiny amount of solder left holding, but it seems likely. It's on one side of that pot - R160 - that you said you had to replace.

Would this explain why the trace appeared to have deflected vertically off the screen?

I'm done reflowing the joints, the IPA has dried, and I'm going to put everything back together and confirm whether it's resolved or not.


Re: Tek 2247A [SN B029000] Recap and diode part list ?

Michael
 

Hi,

I would not recommend replacing the tantalums unless they are known to be bad.
Some people recommend measuring their ESR - but if you do that, you might just
as well replace it because you have done half the work in lifting a lead. I
have NOT replaced my tantalums, so while I know that my other replacements
were functionally correct, all I can do is give you what I would initially
choose from a quick look at Mouser.

Tantalum capacitors generally need to be overspecified. So these choices use a
higher voltage, which matches the other components better than an 85C version.
However, tantalums are not as cheap as aluminum.

A1 Main

A1 C0512 290-0246-00 3.3uF 10% 15V Axial Tantalum T110B335K035AT 3.3uF 35v 10% 125C 3.19
A1 C0536 290-0246-00 3.3uF 10% 15V Axial Tantalum T110B335K035AT 3.3uF 35v 10% 125C 3.19
A1 C0977 290-0246-00 3.3uF 10% 15V Axial Tantalum T110B335K035AT 3.3uF 35v 10% 125C 3.19


A3 Inverter

A3 C1034 290-0524-00 4.7uF 20% 10V Radial Tantalum T350C475K020AT 4.7uF 20v 10% 125C 1.33


A5 (670-9052-02) Digital Control

A5 C2350 290-0527-00 15uF 20% 20V Radial Tantalum T350J156K035AT 15uF 35v 10% 125C 3.91
A5 C2470 290-0527-00 15uF 20% 20V Radial Tantalum T350J156K035AT 15uF 35v 10% 125C 3.91


Mike







Hi Mike,
Thanks for your advice, appreciated.
Based on last 20years technology improvement, what will be today best
replace for those tantalum caps, still go back to tantalum or there are more reliable alternative part?
2247A power supply can not find tantalum caps, mostly use in process or main board.
My unit look like having leaky diode as well on CR2227 and CR2228, reverse
diode test [on-board] give me reading 0.51v forward voltage give me 0.45.
I think this could be the cause for my burn mark on PCB.

From: "2465bct@... [TekScopes]" <TekScopes@...>
To: "TING HENG CHING darren_ting_hc@... [TekScopes]" <TekScopes@...>
Sent: Sunday, 13 March 2016, 23:26
Subject: Re: [TekScopes] Tek 2247A [SN B029000] Recap and diode part list ?

  If the 2247A service manual is like the 2465B service manual, it does not
distinguish between aluminium and tantalum capacitors. Nor do they distinguish
between axial and radial or polar and bipolar. All of those distinctions have
to be determined by manual inspection of the boards. Unless, you can tell from
the Tektronix part number, which is usually not very informative.

When I recapped my 2465BCT, I made a complete list, but then once I had the
boards out I had to refine my list to take those considerations into account.
Unless someone else has a list they actually used, recapping can take a while
due to the need for multiple, serial orders.

The problem is that you usually don't want to take these boards out more than
necessary and for some of them it is had to inspect the parts without removing
the boards. For the 2465BCT, the processor board, the main power and the high
voltage boards can be inspected fairly easily. The power supply boards, option
boards, etc., not so much.

Mike
>> Based on service manual for 2247A, I can't  find Tantalum cap, am I missing something?

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--
Best regards,
2465bct mailto:2465bct@...


Re: Tek 2247A [SN B029000] Recap and diode part list ?

Darren Ting
 

Hi David,
Thanks, yes you are right, reverse voltage drop of CR2227 and CR2228 actually belong to base-emitter junctions of Q2209 and Q2210 after re-look a the circuit diagram.
Now I really lost what to do next.

Any advice why this area get so hot till cause a scorch mark on PCB?

I have the picture but not sure how to attached it in here


From: "David @DWH [TekScopes]" <TekScopes@...>
To: TekScopes@...
Sent: Monday, 14 March 2016, 9:39
Subject: Re: [TekScopes] Tek 2247A [SN B029000] Recap and diode part list ?

  On Mon, 14 Mar 2016 00:03:35 +0000 (UTC), you wrote:

Hi Mike,
Thanks for your advice, appreciated.
Based on last 20years technology improvement, what will be today best replace for those tantalum caps, still go back to tantalum or there are more reliable alternative part?
If I replaced them at all, I would use solid tantalums; they have
better high frequency performance than aluminum electrolytic
capacitors. Aluminum and tantalum polymer capacitors have much lower
ESR which could cause problems in some cases and they also degrade
with time unlike solid tantalum capacitors; water attacks their solid
organic polymer dielectric.

I agree with what Jerry said; the only reason to replace the solid
tantalum capacitors is if the originals were not sufficiently voltage
derated.

If you do want to replace a solid tantalum capacitor with an aluminum
electrolytic capacitor which will be less expensive although not
decisively so, use a low ESR and high frequency aluminum electrolytic
capacitor with about 4 times the capacitance to get an equivalent D
and ESR.

2247A power supply can not find tantalum caps, mostly use in process or main board.
Solid tantalum capacitors are only common for local bulk decoupling
and where a large value is needed with low leakage. They do not
economically support the high ripple current requirements for the
input and output capacitors in a high power switching power supply.

My unit look like having leaky diode as well on CR2227 and CR2228, reverse diode test [on-board] give me reading 0.51v forward voltage give me 0.45.
I think this could be the cause for my burn mark on PCB.
If leakage raised the temperature enough to cause a scorch mark, then
the diode would have failed do to thermal runaway.

When you measure the reverse voltage drop of CR2227 and CR2228, you
see the forward voltage drop of the base-emitter junctions of Q2209
and Q2210. I think those diodes protect against reverse base-emitter
breakdown.
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[Non-text portions of this message have been removed]


Re: Tek 2247A [SN B029000] Recap and diode part list ?

 

On Mon, 14 Mar 2016 00:03:35 +0000 (UTC), you wrote:

Hi Mike,
Thanks for your advice, appreciated.
Based on last 20years technology improvement, what will be today best replace for those tantalum caps, still go back to tantalum or there are more reliable alternative part?
If I replaced them at all, I would use solid tantalums; they have
better high frequency performance than aluminum electrolytic
capacitors. Aluminum and tantalum polymer capacitors have much lower
ESR which could cause problems in some cases and they also degrade
with time unlike solid tantalum capacitors; water attacks their solid
organic polymer dielectric.

I agree with what Jerry said; the only reason to replace the solid
tantalum capacitors is if the originals were not sufficiently voltage
derated.

If you do want to replace a solid tantalum capacitor with an aluminum
electrolytic capacitor which will be less expensive although not
decisively so, use a low ESR and high frequency aluminum electrolytic
capacitor with about 4 times the capacitance to get an equivalent D
and ESR.

2247A power supply can not find tantalum caps, mostly use in process or main board.
Solid tantalum capacitors are only common for local bulk decoupling
and where a large value is needed with low leakage. They do not
economically support the high ripple current requirements for the
input and output capacitors in a high power switching power supply.

My unit look like having leaky diode as well on CR2227 and CR2228, reverse diode test [on-board] give me reading 0.51v forward voltage give me 0.45.
I think this could be the cause for my burn mark on PCB.
If leakage raised the temperature enough to cause a scorch mark, then
the diode would have failed do to thermal runaway.

When you measure the reverse voltage drop of CR2227 and CR2228, you
see the forward voltage drop of the base-emitter junctions of Q2209
and Q2210. I think those diodes protect against reverse base-emitter
breakdown.


Re: 7854 Repair & Restoration

 

That is the way I remember it but it was years ago when I removed the
vertical amplifier from my 7854 to replace the gain control trimmer.

The support rails have holes providing access to the mounting screws;
these holes are present even on my oldest 7834 so I think disassembly
was intended to be done in this way. Once the screws are removed, the
amplifier board can be slid up and then down to get the aluminum plate
behind the board free of the support rails. I then used needle nose
pliers to reach behind the board and pull collet socket pins straight
out and off of the CRT deflection plate leads.

The first time I did this with my oldest 7834, I unsoldered the wire
leads from the collet socket pins which were pressed onto the CRT
deflection plate leads. I did not even notice the collet socket pins
until I had it apart and wondered, "why are these CRT deflection plate
leads so thick?"

On 13 Mar 2016 16:46:12 -0700, you wrote:

Oy! nevermind, I figured it out with my handy mirrors and a flashlight.

For those that may reference this in the future:

After removing the screws that hold the actual board im place, the whole thing with the blackplate slides up and then the backplate will clear the framework. Just gotta slide it back and remove the socket connectors off the CRT pins first...


Re: 7854 RAM card upgrade only - any interest?

Cliff Carrie
 

I agree. The C4xx series of caps are used as supply voltage bypass in almost all cases (on A25, A28, A31 and A36 at least). A3C430 is an anomaly.

You might be able to test by unplugging the ribbon cable on A3. It would disable the front keyboard and lights but not the external oKB, I think, and you could look at the waveforms again. Floating P108 pin 5 would be another way, but not easily done.


The LED drive lines on A3 are also decoupled by 0.1uf, but they are C1xx and C2xx so are probably not part of the same design decisions.


C430 was installed at SN B010151 according to my manual, which may be only the 51st 7854 produced. I think it has been overlooked, in part because it is shown at the far end of the keyboard cable wiring and nothing other than C430 is on that line in the A3 diagram. In reality, the point to point wiring is not that way; the ribbon cable goes from the MPU top connector to the A3 board, and continues from there to the rear connector board.


The changes made at SN B010151 are a grab bag of minor parts value modifications, mostly resistors in power supply areas. None of the 8 affected circuit boards changed part number, so Tek apparently did not consider any of these changes mandatory. I don't think any of the changes were revisited after B010151.


Cliff


Herd Thinning

Bill Higdon
 

I have the following scopes for sale in the Pacific North Wet, I'll make arrangements to meet someone but I will not ship them.

Tek 7504 with 2 7A11's 1 of which has 1 bad channel, 7B50, & 7B51 $150
Tek 7854 with 2 7A26's, 7B85, 7D10 & keyboard $250
Tek 545B with 1A2, 1L5, 1L10 and Scope cart $100

Bill Higdon


Re: Tek 2247A [SN B029000] Recap and diode part list ?

Darren Ting
 

Hi Mike,
Thanks for your advice, appreciated.
Based on last 20years technology improvement, what will be today best replace for those tantalum caps, still go back to tantalum or there are more reliable alternative part?
2247A power supply can not find tantalum caps, mostly use in process or main board.
My unit look like having leaky diode as well on CR2227 and CR2228, reverse diode test [on-board] give me reading 0.51v forward voltage give me 0.45.
I think this could be the cause for my burn mark on PCB.


From: "2465bct@... [TekScopes]" <TekScopes@...>
To: "TING HENG CHING darren_ting_hc@... [TekScopes]" <TekScopes@...>
Sent: Sunday, 13 March 2016, 23:26
Subject: Re: [TekScopes] Tek 2247A [SN B029000] Recap and diode part list ?

  If the 2247A service manual is like the 2465B service manual, it does not
distinguish between aluminium and tantalum capacitors. Nor do they distinguish
between axial and radial or polar and bipolar. All of those distinctions have
to be determined by manual inspection of the boards. Unless, you can tell from
the Tektronix part number, which is usually not very informative.

When I recapped my 2465BCT, I made a complete list, but then once I had the
boards out I had to refine my list to take those considerations into account.
Unless someone else has a list they actually used, recapping can take a while
due to the need for multiple, serial orders.

The problem is that you usually don't want to take these boards out more than
necessary and for some of them it is had to inspect the parts without removing
the boards. For the 2465BCT, the processor board, the main power and the high
voltage boards can be inspected fairly easily. The power supply boards, option
boards, etc., not so much.

Mike

Based on service manual for 2247A, I can't  find Tantalum cap, am I missing something?
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Re: 7854 Repair & Restoration

Brian Bloom
 

Oy! nevermind, I figured it out with my handy mirrors and a flashlight.

For those that may reference this in the future:

After removing the screws that hold the actual board im place, the whole thing with the blackplate slides up and then the backplate will clear the framework. Just gotta slide it back and remove the socket connectors off the CRT pins first...


Re: 7854 Repair & Restoration

Brian Bloom
 

Is there some kind of procedure for removing this board that I'm not finding?

It appears to me like I have to remove the entire mounting plate that bolts to the frame rail, rear CRT mounting plate, the mounting plate behind that, and the plate that the horizontal amp board is mounted to.

If I don't go that route, it looks like I'd need to unbolt U150 from the secondary plate that is behind the vertical amp board/plate. Doung so would risk damaging the two leads that go to the CRT tube from U150.

Is there no easier way?


Re: Raindrops on a Scope

Jim McIntyre
 

Sweet - thanks for posting...


Re: 2465B Recap Project

John Dickens <jake_117_dickens@...>
 

Mike,

I can’t tell you how much I appreciate this list. Thanks a million

John

On Mar 13, 2016, at 8:31 AM, 2465bct@... [TekScopes] <TekScopes@...> wrote:

John,

John, I recently completely recapped all boards on my 2465BCT, s/n B010xxx so
my parts list should work for you. I did not replace the tantalum capacitors,
but my list identifies them. I ordered all parts from Mouser. I included the
Mouser cost, sometimes I hit a volume breakpoint but usually not.

A1 Main

A1 C0102 290-0973-00 100uF 20% 25VDC UPW1V101MPD 100uF 35V 20% 105c 0.24
A1 C0107 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0114 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0121 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0130 290-0776-01 22uF 20% 10V UPW1E220MDD 22uF 25V 20% 105c 0.16
A1 C0152 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0185 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0218 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0221 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0307 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0325 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0335 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0512 290-0246-00 3.3uF 10% 15V Axial Tantalum
A1 C0536 290-0246-00 3.3uF 10% 15V Axial Tantalum
A1 C0723 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0731 290-0944-01 220uF 20% 10V UPW1C221MPD 220uF 16V 20% 105c 0.25
A1 C0732 290-0944-01 220uF 20% 10V UPW1C221MPD 220uF 16V 20% 105c 0.25
A1 C0733 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0738 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0740 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A1 C0957 290-0804-00 10uF +50-20% 25V UPW1V100MDD 10uF 35V 20% 105c 0.16
A1 C0977 290-0246-00 3.3uF 10% 15V Axial Tantalum


A2A1 Regulator

A2A1 C1016 282-1222-00 0.068uF 20% 250V X2 Film ECQ-U2A683KL 0.068uF 250V 10% 100c 0.47
A2A1 C1018 282-1222-00 0.068uF 20% 250V X2 Film ECQ-U2A683KL 0.068uF 250V 10% 100c 0.47

A2A1 C1220 290-0939-00 10uF +100-10% 100V UPW2A100MED 10uF 100V 20% 105c 0.23
A2A1 C1240 290-0939-00 10uF +100-10% 100V UPW2A100MED 10uF 100V 20% 105c 0.23
A2A1 C1260 290-0942-00 100uF +100-10% 25V UPW1V101MPD 100uF 35V 20% 105c 0.24
A2A1 C1274 290-0778-00 1uF 20% 50V Bipolar UEP2A010MDD 1uF 100V 20% 105C 0.51
A2A1 C1280 290-0942-00 100uF +100-10% 25V UPW1V101MPD 100uF 35V 20% 105c 0.24
A2A1 C1291 290-0778-00 1uF 20% 50V Bipolar UEP2A010MDD 1uF 100V 20% 105C 0.51
A2A1 C1292 290-0778-01 1uF +20% 50V Bipolar UEP2A010MDD 1uF 100V 20% 105C 0.51
A2A1 C1300 290-0942-00 100uF +100-10% 25V UPW1V101MPD 100uF 35V 20% 105c 0.24
A2A1 C1330 290-0942-00 100uF +100-10% 25V UPW1V101MPD 100uF 35V 20% 105c 0.24
A2A1 C1350 290-0942-00 100uF +100-10% 25V UPW1V101MPD 100uF 35V 20% 105c 0.24
A2A1 C1400 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A2A1 C1402 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212

A2A1 R1010 301-0150-00 15 Ohm 5% 250V 0.5W Film PR01000101509JR500 15 350V 5% 1W 0.18
A2A1 R1019 301-0150-00 15 Ohm 5% 250V 0.5W Film PR01000101509JR500 15 350V 5% 1W 0.18
A2A1 R1018 301-0300-00 30 Ohm 5% 250V 0.5W Film PR01000103009JR500 30 350V 5% 1W 0.18
A2A1 R1011 315-0560-00 56 Ohm 5% 250V 0.25W Film PR01000105609JR500 56 350V 5% 1W 0.18
A2A1 R1012 315-0560-00 56 Ohm 5% 250V 0.25W Film PR01000105609JR500 56 350V 5% 1W 0.18
A2A1 R1016 301-0680-00 68 Ohm 5% 250V 0.5W Film PR01000106809JR500 68 350V 5% 1W 0.18
A2A1 R1013 315-0683-00 68k Ohm 5% 250V 0.25V Film PR01000104703JR500 68k 350V 5% 1W 0.18
A2A2 R1017 315-0474-00 470K Ohm 5% 250V 0.25W Film PR01000104703JR500 470k 350V 5% 1W 0.18

A3 Inverter

A3 C1020 285-1192-00 0.0022uF 20% 250V X2 Film ECQ-U2A222KL 0.0022uF 250V 10% 100C 0.51
A3 C1051 285-1192-00 0.0022uF 20% 250V X2 Film ECQ-U2A222KL 0.0022uF 250V 10% 100C 0.51
A3 C1052 285-1196-00 0.01uF 20% 250V X2 Film ECQ-U2A103KL 0.01uF 250V 10% 100C 0.49

A3 C1021 290-0971-00 290uF +50-10% 200V Axial TVX2D331MDD 330uF 200V 20% 85C 7.19
A3 C1022 290-0971-00 290uF +50-10% 200V Axial TVX2D331MDD 330uF 200V 20% 85C 7.19
A3 C1025 290-0942-00 100uF +100-10% 25V UPW1V101MPD 100uF 35V 20% 105C 0.24
A3 C1034 290-0524-00 4.7uF 20% 10V Radial Tantalum
A3 C1066 290-0782-01 4.7uF 20% 35V UPW1H4R7MDD 4.7uF 50V 20% 105C 0.16
A3 C1072 290-0806-00 3.3uF +75-10% 350V UPW2V3R3MPD 3.3uF 350V 20% 105C 0.53
A3 C1101 290-0942-00 100uF +100-10% 25V UPW1V101MPD 100uF 35V 20% 105C 0.24
A3 C1102 290-0942-00 100uF +100-10% 25V UPW1V101MPD 100uF 35V 20% 105C 0.24
A3 C1110 290-0800-00 250uF +100-10% 20V UPW1H331MPD 330uF 50V 20% 105C 0.51
A3 C1111 290-0800-00 250uF +100-10% 20V UPW1H331MPD 330uF 50V 20% 105C 0.51
A3 C1112 290-0782-01 4.7uF 20% 35V UPW1H4R7MDD 4.7uF 50V 20% 105C 0.16
A3 C1113 290-0798-00 180uF +100-10% 40V UPW1H331MPD 330uF 50V 20% 105C 0.51
A3 C1114 290-0800-00 250uF +100-10% 20V UPW1H331MPD 330uF 50V 20% 105C 0.51
A3 C1115 290-0800-00 250uF +100-10% 20V UPW1H331MPD 330uF 50V 20% 105C 0.51
A3 C1116 290-0798-00 180uF +100-10% 40V UPW1H331MPD 330uF 50V 20% 105C 0.51
A3 C1120 290-0939-00 10uF +100-10% 100V UPW2A100MED 10uF 100V 20% 105C 0.23
A3 C1130 290-0939-00 10uF +100-10% 100V UPW2A100MED 10uF 100V 20% 105C 0.23
A3 C1132 290-0880-00 10uF +50-10% 160V UPW2C100MPD 10uF 160V 20% 105C 0.39

Note: C1115 and C1132 are reversed in the service manual layout. Double check actual values when replacing.

Note: C1021 and C1022 are axial, but the originals have much longer leads than available now.
The leads on the replacements will need to be extended. I cut the leads from the original
and soldered them to the replacement leads. That is tricky to keep them from unsoldering.
Now, I might use a very fine wire thread and bind the leads together then solder over that
so the wire thread will hold it together if the solder gets too hot.

A5 (670-9052-02) Digital Control

A5 C2010 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A5 C2011 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A5 C2113 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A5 C2350 290-0527-00 15uF 20% 20V Radial Tantalum
A5 C2420 290-0943-02 47uF 20% 25V UHV1V470MDD 47uF 35V 20% 105c 0.212
A5 C2470 290-0527-00 15uF 20% 20V Radial Tantalum


Mike





Does anyone have a list of capacitors they have purchased to recap the A1,
A1A2, A3 and A5 boards or an early 2465B (Serial number around B015000)? I
would like to use the most appropriate caps.

Thanks, John



--
Best regards,
2465bct mailto:2465bct@... <mailto:2465bct@...>



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Yahoo Groups Links



Re: 7A13 Knob

John Dickens <jake_117_dickens@...>
 

Nathan,

I too need the big knob for my 7A13. If anyone makes knobs, I would like to buy one.

John





On Mar 12, 2016, at 3:15 PM, Nathan Johnson jdownj@... [TekScopes] <TekScopes@...> wrote:

I'm going to buy the used knob from the member who offered it above, and then
try to make several Tek knobs.
A coworker with a lathe is making metal inserts, and with some decent CAD, I'll
probably send the files to Shapeways. Probably won't be anything like perfect
looking, but functional.
Nathan KK4REY

Sent using CloudMagic Email
[https://cloudmagic.com/k/d/mailapp?ct=pi&cv=7.4.15&pv=9.1&source=email_footer_2 <https://cloudmagic.com/k/d/mailapp?ct=pi&cv=7.4.15&pv=9.1&source=email_footer_2>]
On Sat, Mar 12, 2016 at 15:29, @Raymond <mailto:@Raymond> [TekScopes]
<TekScopes@... <mailto:TekScopes@...>> wrote:
The problem with the "replacement" knob on the 'bay is that the Al insert is
more in front (from the faceplate) than with the original. The hex fastening
screw is as well. I'm not at all convinced that it (the inner knob) would fit,
even after removing the plastic black insert. I have both one of those knobs (I
think). I'll be in my lab again early next week and can try if it fits my 7A13.

Raymond

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[Non-text portions of this message have been removed]


Re: OT 10Mhz references

Greg Muir
 

I'm sure that somewhere in Tom Van Baak's basement is an ongoing project to construct a Cesium fountain atomic clock. Then the HP Cesium units may come up for sale.

Greg


Re: OT 10Mhz references

mosaicmerc
 

Yes, well I don't have the $$ for a GPSDO right now so I am going the DIY way wth a Trimble OCXO 65256 12V, 10MHZ sine.
It'll certainly be around 2 orders better than the internal TCXO in the SA or VNA. Improved Phase noise as well no doubt.
I don't know if I'll see a better noise floor on the instruments as a result. On the SA I can get down to around -149dBm/Hz median with a 1Mhz span and 300Hz VBW. A 3 dB 'noise' variance is visible from sweep to sweep. SO I'd imagine I could consider measuring a -140dBm/hz noise value as discernable. -130dBm should be easy to see.
Ancel