Date   

Re: Source for premade BNC patch cables or DIY

stefan_trethan
 

Indeed the Swiss are even more special. If they made the crimping tool it would really hurt your bank balance, look for example at the Huber&Suhner crimp tools, they take 4 digits off you for a simple hand tool without even breaking a sweat.
Swiss tools are great, just not proportionally, it is easy to make a fine tool for the remaining 20% if you start that high.

The pressmaster tool may have a practical advantage, the dies are held together as one piece and may be easy to change without screws. The US brand tools mentioned before are virtually identical to the cheap ones, I won't get a practical benefit other than the nice has-once-been-made-in-USA brand warming my heart as long as I don't look at the made in Taiwan sticker.

That's the only way for European and US manufacturers to survive long-term right now, provide something that has an edge over the other model and always stay one step ahead. Many fall by the wayside, they see cost savings by producing in Asia and suddenly one day the product is no longer better, instead it falls behind because innovation is killed by the unwieldy company structure and the product is still more expensive because you need to pay the western owners and staff.

ST


On Sat, Sep 14, 2013 at 11:50 PM, Miroslav Pokorni <mpokorni@...> wrote:


Wasn't that you Stefen, who recently posted a statement to effect that when you have a Swiss piece of tool that 80% of price goes to 'Swiss' and there is not much left for quality? Why would Swedes be much different?

Miroslav Pokorni



On 9/14/2013 4:44 AM, Stefan Trethan wrote:
 
Yes the connector manufacturer sets the size, but (one hopes!) they will all be similar or limit themselves to a couple of sizes.

I don't know if you already know this document, but it will be worth a read if you don't:
<http://www.crimptech.com.au/RF%20Connectors%20&%20Cabling.pdf>
I did have a similar but more extensive American text but can't find it now. Military and aviation instruction manuals and teaching aids are some of the best out there, and often available free since they are already paid for by the taxpayer.

Regarding the pressmaster, I don't think you spent all that much more than I did for my collection of crimpers (albeit mine is somewhat more extensive). I believe pressmaster really is still made in Sweden so you should actually get a superior tool and not just pay for the brand. I wonder how easy the dies are to change on this pressmaster frame, I really don't like to change dies too often since it requires the removal of screws on my pliers, so I have dedicated pliers for most dies. If it is easy with the pressmaster, that might actually be a better system since it won't waste a whole drawer full of pliers you only need once a year.

ST






Re: New guy trying to fix an old Tek scope (442)

Robert Simpson
 

 Hi, I once had a 442 and fixed a problem similar to yours. This was also reported by me on another forum a few years ago: (from that posting)

 

". I have experience with the 442 including fixing the problem you have. I bought one not working about a year ago and completely refurbished it. I then used it for a year when I got a deal on a newer model, then sold my 442.

Here is the short version
That fuse feeds the high voltage supply. I bought a CD manual from QService but gave it away with the new owner. However I still have a printout of the HV CRT section. What I found was the same blown fuse you have. I temporarily put in a 1/10 fast blow until I could order the 1/16 fuse. The scope then showed a trace after about a minute warm up. It blew after a couple of hours of use. When I finally got the service manual, I found that Q458 (? 2SC2333? NTE379?), a power regulating transistor, had been replaced before. So I ordered a replacement as well as the Electrolytic cap C458 (10uf 150V). E-caps are notorious for going bad. After replacing the Xter and cap, the turn on time went down from a minute to 10secs! And it would run for hours. (is there a place to post the schematic .jpg?)

Later I also cleaned the vertical attenuator contacts (caution, be very careful!) and some potentiometers. At one point I was having a strange problem which I traced to the polarity trigger push button switch. I replaced that but after dissecting the old switch found I might have fixed it by just pushing it in and out a hundred or so times. The internal contacts had tarnished from lack of use!

I also found some of the internal wires were breaking loose from the plastic contact carriers. So I re-soldered those. I then gently tugged on all wires and re-soldered any that came loose.
I did several other things including replacing all the large ecaps near the main power supply (Turn on time now down to 3 secs) also added a thin fan for cooling to the back.

Take lots of pictures!!!! It really helps. Also, observed all safety precautions especially those relating to the HV area. I could go into a lot more detail, but it would make a very long post.

 

Bob


--- In tekscopes@..., <tmiller11147@...> wrote:

My first guess would be that C458 is shorted. Is it a tantalum capacitor? If R458 glowed, it should be replaced. It is a 150 ohm, 3 watt 5% wire wound unit.
 
Regards,
Tom
 
 
 
----- Original Message -----
From: pr0phetex
Sent: Saturday, September 14, 2013 5:44 PM
Subject: [TekScopes] New guy trying to fix an old Tek scope (442)

 

Hi everybody! I'm an electronics hobbyist looking for some advice. I found an old Tektronix 442 scope near me for $25 and thought it would be a good choice for a first scope, provided I can get it to work again. I have a Fluke 87 III to measure with, but I don't have a hv probe right now (I could get one if needed).

So here's the problem: I'm getting a pilot light but no trace on the screen. All the outputs on the power supply board are good except the 100v unregulated output which measured around 77v. The 1/16th amp fuse (F722) is blown but I'm not sure whats causing such a high current draw. When I measure the current through across the fuse terminals I'm seeing 170ma and rising. When I left this on for a min several of the transistors got hot but I saw resistor 458 get extremely hot (glowing). I couldn't find any of the transformer coils shorted. Any suggestions on what could be wrong? I am not afraid of replacing parts and I'm not too bad at soldering, but I don't want to start throwing parts at it without understanding what's wrong. Is the resistor bad? It looks like the resistance has lowered.

Here's the manual: http://www.box.net/shared/0jn2bd5njp

Thanks!


Re: How on earth do you OPEN a Tek 222PS portable?

Don Black <donald_black@...>
 

Hello Walter,
                        I don't have one of these but found the maintenance manual on TekWiki and had a look at it. Page 6-9 has full details on removing the case. Since it's a full page, better you look at the manual than me describing it.

Hope this helps, Don Black.

On 15-Sep-13 8:07 AM, walter2@... wrote:
 

I am trying to fix one of these yellow marvels, but even after removing all the case screws I can find, it won't come apart. very frustrating. I am also searching for a battery and probes for this, if I can ever get it working.

all advice and help appreciated,
walter  (walter2 -at- sphere.bc.ca)
sphere research



Re: 2465B Low Voltage Power Supply testing

 

David:


It is on my 2465B, and I believe for serials over B05xxxx (only a guess on that front though). Uploaded a pic of the portion of the schematic.


http://groups.yahoo.com/neo/groups/TekScopes/photos/albums/888008784/lightbox/525688445




--- In TekScopes@..., <tekscopes@...> wrote:

Which revisions have C1292 or where does it connect? I could not find it in any of my 2465 series documentation.

On 14 Sep 2013 11:23:30 -0700, you wrote:

>. . .
>
>For the spreadsheet the newark part number for the 1uf BI-polar caps C1274/C1291 is wrong, comes up with a film capacitor. Some suggest a film cap is fine, but for me, Tek designed it for a Bi-polar for some reason so that is what I used. Note that some revisions of the power supply use 3 BI-polars C1292, next to C1291
>
> . . .


Re: 2465A +5vd Power Supply Problem

 

There is no indication Tektronix was grading them for CTR so I assume they compensated the regulator's feedback loop to handle the worse
case which will be high CTR.

On 14 Sep 2013 02:09:16 -0700, you wrote:

David:

Just on your point about opto not having a tightly controlled CTR, would this not be something to consider when replacing. I know there is two variants of the TLP631. "F" Current transfer ratio: 50% (min.) "GB": 100% (min.) from a discussion earlier. Other cross references have similar specs, for example the 4n35 which is a cross reference I believe is 100% at IF = 10 mA


Re: 2465B Low Voltage Power Supply testing

 

At least in this case the capacitors are part of operational amplifier feedback networks so high power is not a problem.

On Sat, 14 Sep 2013 18:17:29 -0400, you wrote:

I like film caps, but note that their "self-healing" doesn't work well at very
high power levels where the energy of the fault is sufficient to induce failure
in adjacent layers. Those capacitors exploding can be quite loud, and the
vegetable oil filled ones will make a big mess.

Peter

On 9/14/2013 5:47 PM, mosaicmerc wrote:

Regarding choosing electrolytic bipolar over film caps, at the time (25 years
ago) film technology had limitations in certain apps.
Tek used the best parts available, that has changed somewhat 25 years down the
line.

Film is generally better than electrolytic once size/cost permits.

Please consider:
http://www.avx.com/docs/techinfo/filmtech.pdf


Re: 2465B Low Voltage Power Supply testing

 

Which revisions have C1292 or where does it connect? I could not find it in any of my 2465 series documentation.

On 14 Sep 2013 11:23:30 -0700, you wrote:

. . .

For the spreadsheet the newark part number for the 1uf BI-polar caps C1274/C1291 is wrong, comes up with a film capacitor. Some suggest a film cap is fine, but for me, Tek designed it for a Bi-polar for some reason so that is what I used. Note that some revisions of the power supply use 3 BI-polars C1292, next to C1291

. . .


Re: How on earth do you OPEN a Tek 222PS portable?

John Gord
 

Walter,


It's pretty complicated (13 steps).  Get the service manual (free) at ko4bb.com.


--John Gord



--- In TekScopes@..., <tekscopes@...> wrote:

I am trying to fix one of these yellow marvels, but even after removing all the case screws I can find, it won't come apart. very frustrating. I am also searching for a battery and probes for this, if I can ever get it working.

all advice and help appreciated,
walter  (walter2 -at- sphere.bc.ca)
sphere research


Re: How on earth do you OPEN a Tek 222PS portable?

 

Check under labels for hidden screws.
 
 

----- Original Message -----
Sent: Saturday, September 14, 2013 6:07 PM
Subject: [TekScopes] How on earth do you OPEN a Tek 222PS portable?

 

I am trying to fix one of these yellow marvels, but even after removing all the case screws I can find, it won't come apart. very frustrating. I am also searching for a battery and probes for this, if I can ever get it working.

all advice and help appreciated,
walter  (walter2 -at- sphere.bc.ca)
sphere research


Re: 2465B Low Voltage Power Supply testing

Michael A. Terrell
 

Peter Gottlieb wrote:
I like film caps, but note that their "self-healing" doesn't work well at very
high power levels where the energy of the fault is sufficient to induce failure
in adjacent layers. Those capacitors exploding can be quite loud, and the
vegetable oil filled ones will make a big mess.
Not all film caps are self healing. Only the 'X' and 'Y' types are required to meet this spec.


Re: 2465B Low Voltage Power Supply testing

Peter Gottlieb <hpnpilot@...>
 

I like film caps, but note that their "self-healing" doesn't work well at very high power levels where the energy of the fault is sufficient to induce failure in adjacent layers. Those capacitors exploding can be quite loud, and the vegetable oil filled ones will make a big mess.

Peter

On 9/14/2013 5:47 PM, mosaicmerc wrote:


Regarding choosing electrolytic bipolar over film caps, at the time (25 years ago) film technology had limitations in certain apps.
Tek used the best parts available, that has changed somewhat 25 years down the line.

Film is generally better than electrolytic once size/cost permits.

Please consider:
http://www.avx.com/docs/techinfo/filmtech.pdf


Re: New guy trying to fix an old Tek scope (442)

 

My first guess would be that C458 is shorted. Is it a tantalum capacitor? If R458 glowed, it should be replaced. It is a 150 ohm, 3 watt 5% wire wound unit.
 
Regards,
Tom
 
 
 

----- Original Message -----
From: pr0phetex
Sent: Saturday, September 14, 2013 5:44 PM
Subject: [TekScopes] New guy trying to fix an old Tek scope (442)

 

Hi everybody! I'm an electronics hobbyist looking for some advice. I found an old Tektronix 442 scope near me for $25 and thought it would be a good choice for a first scope, provided I can get it to work again. I have a Fluke 87 III to measure with, but I don't have a hv probe right now (I could get one if needed).

So here's the problem: I'm getting a pilot light but no trace on the screen. All the outputs on the power supply board are good except the 100v unregulated output which measured around 77v. The 1/16th amp fuse (F722) is blown but I'm not sure whats causing such a high current draw. When I measure the current through across the fuse terminals I'm seeing 170ma and rising. When I left this on for a min several of the transistors got hot but I saw resistor 458 get extremely hot (glowing). I couldn't find any of the transformer coils shorted. Any suggestions on what could be wrong? I am not afraid of replacing parts and I'm not too bad at soldering, but I don't want to start throwing parts at it without understanding what's wrong. Is the resistor bad? It looks like the resistance has lowered.

Here's the manual: http://www.box.net/shared/0jn2bd5njp

Thanks!


How on earth do you OPEN a Tek 222PS portable?

 

I am trying to fix one of these yellow marvels, but even after removing all the case screws I can find, it won't come apart. very frustrating. I am also searching for a battery and probes for this, if I can ever get it working.

all advice and help appreciated,
walter  (walter2 -at- sphere.bc.ca)
sphere research


Re: New guy trying to fix an old Tek scope (442)

Peter Gottlieb <hpnpilot@...>
 

Well I'd start with that power supply. My experience is that if it is reading low you probably have an open filter capacitor. That would be C722 in your schematic. Set the Fluke to AC Volts and read the unregulated 100 V line, you will probably see a very high amount of AC there. Try jumpering another capacitor across C722.

R458 feeds the HV power supply. You may have a shorted or bad transister there, check Q458 first, another component could be bad, or the HV transformer might have internal breakdown. Is R458 bad? If it was glowing, it is now.

Peter

On 9/14/2013 5:44 PM, pr0phetex wrote:

Hi everybody! I'm an electronics hobbyist looking for some advice. I found an old Tektronix 442 scope near me for $25 and thought it would be a good choice for a first scope, provided I can get it to work again. I have a Fluke 87 III to measure with, but I don't have a hv probe right now (I could get one if needed).

So here's the problem: I'm getting a pilot light but no trace on the screen. All the outputs on the power supply board are good except the 100v unregulated output which measured around 77v. The 1/16th amp fuse (F722) is blown but I'm not sure whats causing such a high current draw. When I measure the current through across the fuse terminals I'm seeing 170ma and rising. When I left this on for a min several of the transistors got hot but I saw resistor 458 get extremely hot (glowing). I couldn't find any of the transformer coils shorted. Any suggestions on what could be wrong? I am not afraid of replacing parts and I'm not too bad at soldering, but I don't want to start throwing parts at it without understanding what's wrong. Is the resistor bad? It looks like the resistance has lowered.

Here's the manual: http://www.box.net/shared/0jn2bd5njp

Thanks!


Re: Source for premade BNC patch cables or DIY

Miroslav Pokorni
 

Wasn't that you Stefen, who recently posted a statement to effect that when you have a Swiss piece of tool that 80% of price goes to 'Swiss' and there is not much left for quality? Why would Swedes be much different?

Miroslav Pokorni


On 9/14/2013 4:44 AM, Stefan Trethan wrote:
�
Yes the connector manufacturer sets the size, but (one hopes!) they will all be similar or limit themselves to a couple of sizes.

I don't know if you already know this document, but it will be worth a read if you don't:
<http://www.crimptech.com.au/RF%20Connectors%20&%20Cabling.pdf>
I did have a similar but more extensive American text but can't find it now. Military and aviation instruction manuals and teaching aids are some of the best out there, and often available free since they are already paid for by the taxpayer.

Regarding the pressmaster, I don't think you spent all that much more than I did for my collection of crimpers (albeit mine is somewhat more extensive). I believe pressmaster really is still made in Sweden so you should actually get a superior tool and not just pay for the brand. I wonder how easy the dies are to change on this pressmaster frame, I really don't like to change dies too often since it requires the removal of screws on my pliers, so I have dedicated pliers for most dies. If it is easy with the pressmaster, that might actually be a better system since it won't waste a whole drawer full of pliers you only need once a year.

ST



Re: 2465B Low Voltage Power Supply testing

mosaicmerc
 

Regarding choosing electrolytic bipolar over film caps, at the time (25 years ago) film technology had limitations in certain apps.
Tek used the best parts available, that has changed somewhat 25 years down the line.

Film is generally better than electrolytic once size/cost permits.

Please consider:
http://www.avx.com/docs/techinfo/filmtech.pdf


New guy trying to fix an old Tek scope (442)

pr0phetex
 

Hi everybody! I'm an electronics hobbyist looking for some advice. I found an old Tektronix 442 scope near me for $25 and thought it would be a good choice for a first scope, provided I can get it to work again. I have a Fluke 87 III to measure with, but I don't have a hv probe right now (I could get one if needed).

So here's the problem: I'm getting a pilot light but no trace on the screen. All the outputs on the power supply board are good except the 100v unregulated output which measured around 77v. The 1/16th amp fuse (F722) is blown but I'm not sure whats causing such a high current draw. When I measure the current through across the fuse terminals I'm seeing 170ma and rising. When I left this on for a min several of the transistors got hot but I saw resistor 458 get extremely hot (glowing). I couldn't find any of the transformer coils shorted. Any suggestions on what could be wrong? I am not afraid of replacing parts and I'm not too bad at soldering, but I don't want to start throwing parts at it without understanding what's wrong. Is the resistor bad? It looks like the resistance has lowered.

Here's the manual: http://www.box.net/shared/0jn2bd5njp

Thanks!


545 on Durham, North Carolina Craigslist

sipespresso <sipespresso@...>
 


Re: Hakko Soldering Station Handles

stefan_trethan
 

I don't know the difference, but be warned that Hakko are probably the world's most counterfeit irons.
Besides the many clones with different names there are outright forgeries which are sold as genuine Hakko 907.
That may be the reason for the $10 offers.

Make sure to get a genuine product or make sure it is at least cheap enough for a fake.

ST


On Sat, Sep 14, 2013 at 7:11 PM, David C. Hallam <david.hallam@...> wrote:
Can anyone tell me the differences between a Hakko 900M handle and a 907
handle?

I just picked up a Hakko 928 soldering station which has outlets for 2
handles.  It has one 900M handle.  The manual lists both the 900 and 907
handles as usable with the 928 station.  However when I check prices on
eBay I see 907's listed for about $10 while 900's are more like $80-90
so there must be a big difference.

David
KW4DH


--
Before I came here I was confused about this subject.  Having listened
to your lecture I am still confused. But on a higher level.
Enrico Fermi


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Re: 2465B Low Voltage Power Supply testing

 

Hi Steve:


All manuals appear to be numbered different if scanned so no point giving a page number, but on my manual, in the 12/13 Regulator Troubleshooting Flowcharts the notation is to the left of the schematic (see below). The notation for the 2 ohm 25 watt resistor for the +5d is 2 pages previous. For 42v and 87v size the wattage and resistance according to the Theory of operation guide in the service manual on their maximum output.


For the spreadsheet the newark part number for the 1uf BI-polar caps C1274/C1291 is wrong, comes up with a  film capacitor. Some suggest a film cap is fine, but for me, Tek designed it for a Bi-polar for some reason so that is what I used. Note that some revisions of the power supply use 3 BI-polars  C1292, next to C1291


R1010/1019/1020 if ordered using the Newark number are physically too big. I source the following instead.


http://canada.newark.com/vishay-bc-components/pr02000201509jr500/resistor-metal-film-15-ohm-2-w/dp/53M5216


http://canada.newark.com/vishay-bc-components/pr02000202703jr500/resistor-metal-film-270-kohm-2/dp/94C2486


Capacitor C1025 with the Newark number is the wrong size. I sourced instead  http://www.newark.com/epcos/b32672l1103j/capacitor-pp-film-0-01uf-600v-5/dp/29M0438


I did not bother replacing the 2 big spragues C1021/C1022. From what I have read they rarely will go bad, only in a surge, lightning situation. Mine were fine in value and ESR anyways.


Caps C1110 -C116 suggest a replacement  of 330uf, I used 220uf for the 180uf replacements, unfortunately did not make a note of the part number, but they were quality Nichicon or Panasonic. Not sure why the author states 330uf for all?


I also replaced R1072 with a  higher wattage resistor, only because during the testing if you leave the regulators unloaded the supply will start whistling and this resistor and Q1062 will get very hot. Ended up scorching the resistor.


I also replaced R1352 and 1352 as apparently they get a workout and could go out of spe




Regulator Repair Notes


Hints for troubleshooting a faulty supply Regulator:


1. First verify that the +10-VREF level is correctly

adjusted; if it is not, do so (see Adjustment Procedure

in Section 5).


2. Regulator output is high:

Is the output loaded?


All Regulators

(except +10-VREF) require some load to

regulate, the lower voltage supplies requiring

greater loads. The Regulators between

+ 15 V and - 1 5 V may be loaded using

100-ohm resistors of the proper

power ratings.


.....



--- In tekscopes@..., <steve65@...> wrote:

Hi bpl521,

Thanks for that info. I've looked through the service manual for info on
how to load the +5, +15, -5, -8 and -15 volt outputs, didn't find it.
Where is it?

The spreadsheet from the archives has been my starting point, so please
let me know of any glitches you ran into in using it.

Steve

On 9/13/2013 5:10 PM, bpl521@... wrote:
>
>
> I can assist you here from the work i have done trying to repair a
> 2465A power supply. If you want to PROPERLY load the supply then you
> need to follow the recommendations in the schematic and load all the
> outputs.
>
>
> 2 ohm 25 watt on +5d. 100 ohm 10 watt resistors on the +5,+15,-15, -5
> v, -8v,
>
>
> On the 87v I used a 2k resistor. In the theory of operation in the
> service manual. 87v rail should not exceed 100ma. -8v rail should not
> exceed 480ma.. +42v rail should not exceed 400ma. I used a 150 ohm
> resistor
>
>
> I did not find it necessary to load the +10v reference.
>
>
> As for connections I will post later as I don't have the boards in
> front of me.
>
>
>
>
>
>
>
> --- In tekscopes@..., <steve65@...> wrote:
>
> I have the LVPS removed from a 2465B in preparation for replacing
> capacitors and a few resistors. The LVPS is still an assembled unit -- I
> have not separated the inverter board from the regulator board. My goal
> is power it up before doing any compon replacement and make some
> "before" observations. Upon completion of the component replacement
> activity I would make "after" observations. Need some advice about a few
> points.
>
> The obvious thing to look for is ripple on the outputs: 5VDC, 15VDC,
> 42VDC and 87VDC. Anything else I should be attentive to as I make
> "before" and "after" measurements?
>
> Based on past postings, I understand that loads for the 5VDC, 42VDC and
> 87VDC outputs. With loads on those outputs, the LVPS should function
> properly, right? Do I need a load on the 15VDC output?
>
> Where is the best place and what is the best way to connect resistive
> loads to the outputs?
>
> My ripple observations would be made with a TEK 2235 powered from the
> same 120VAC circuit as the LVPS. I would connect the 2235 probe's ground
> clip to an LVPS chassis ground point such as J122-4. Will the LVPS
> chassis ground be at the same potential as the 2235 chassis ground?
>
> Steve
>
>
>

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