#687
Edited

Top row, left to right?
Battery current meter- 2 ranges 0-50mA and 0-500mA. Eni CDV-700 draws about 55mA, a single 100 or 200mA would be fine.
Bare, transformerless, Eni CDV-700 PCB, updated with critical parts replaced/restored (more on range switch rebuilding later)
Transistor leakage/Gain tester, built by moi about 55-60 years ago from a HealthKit. Today I would make it myself from scratch (circuit will be provided)

Second row L-R
Substitute original ENi CDV-700 transformer with 18" std. color coded PtFE wires Bk=1, Red=2 Org=3 Yel-4 Grn-5 Blu-6, sorry Violet stayed home (made this last night)
Substitute CDV-700 meter with 18" color coded wires
Universal bench I/O PCB test jig. Besides the soldering iron, this is my most used bench tool!

Details of these and other test items to follow in later posts

Geo

Cover_1.jpg

#688

All transistor electronics in the late 50's and early 60's available to the general public, used germanium PNP transistor with rare exception. We didn't even have silicon rectifiers until much later in the 60's.
These circuits were always POSITIVE GROUND, as are the ENi CDV-700. This causes a lot of confusion to service technicians who were used to negative grounded tube circuits, since forever. I remember watching the Raytheon ads in the monthly trade magazines, showing the CK-722 glass, germanium transistor with prices, they were Expensive! finally when they came down to a dollar, I considered buying one but did not, as in those days the average salary was $1 per hour, and gasoline was 30cents per gallon.? A popular Earl Schieb TV ad said " I will paint ANY CAR for $29.95!".

At the surplus stores a WW2 ARC shortwave receiver set could be bought for $5, but an industrious youngster could fill his bicycle baskets with trash-canned old radios and TV sets all day long for nada. I can't say how many Muntz 5-tube wonder TV sets I scrapped for parts, unsoldering every resistor and capacitor, straightening their leads, sorting into small raisin boxes, and cigar boxes. boxes for storage and later use. every screw, terminal strip, switch, transformer and tube were likewise recycled into my preteen inventory.

Early automobile broadcast radios that proudly displayed "Transistorized", didn't necessarily mean all-transistor by any means. Those hybrid radios used starved-circuit vacuum tubes for most everything except audio, as the transistors of that day were low frequency devices. As technology quickly progress, more and more stages within radios became transistorized.

Germanium transistors are finicky and have unique failures that are not always easy to diagnose. Leakage is one of those issues.

This simple little tester is perfect for checking that parameter. If it shows leaky, twist its wires together* and scrap it. It also has uses in matching transistors or comparing two of the same part # for better gain ones, where that is important. The Leakage/Gain switch is spring loaded to the Leakage position, insuring the first / most important test is done the instant the transistor is plugged in. My unit was modified for external battery holder, it's not something you use everyday and forgotton internal batteries can leak.

Yes there are many complex/expensive transistor testers out there today, but they can be tedious, confusing and really allow simple common faults to slip by.

The IT-10 was what we had back in the day and it was all we needed, then and now, when working on CDV-700 era stuff.

Schematic attached.

Geo
Germanium Transistor Leakage Tester.jpg

Germanium Transistor Leakage Tester.jpg

Heathkit-IT-10-Schematic.pdf

#689

geo

i have the same heathkit tr checker
it just a different colour. i got mine for $1 at ham club swap meet. i also have a radio shack tr tester that uses the transistor in an oscillator to light a neon bulb. it gives a crude relative gain estimate

p

#690

开云体育

Does anyone here have a manual for a Lectrotech Model TT-250 In-Circuit Transistor Analyzer?? I have one that seems to have issues, and do not understand how it is supposed to be used.? I have had no luck finding a manual or schematic.? Even finding someone that has a working one and/or knows how to use it properly would be good.? Here’s the most info I have found on it: ?? There are picture on eBay of one or more of them.? It does transistors and diodes.? Mine seems to have auto-biasing issues, and the leakage currents may be inaccurate.? High and low Beta ranges don’t line up well.? The in-circuit test mode seems to have problems due to switches that need to be cleaned, but does work for Beta Checks.? I will have to tear into it at some point, but it wasn’t a cheap tester in its day so I’d like to get it tuned up and 100% working as it seems to have a lot of potential.

I have been testing some Germanium transistors and getting “interesting” results with my Multi-Function Tester-TC1.? I’ll post the data after I get it all entered.

?

Clay Scott

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of peter via groups.io
Sent: Monday, May 23, 2022 2:20 PM
To: [email protected]
Subject: Re: [CDV700CLUB] CDV-700 Transformer Tester and other essential shop-made service tools

?

geo

i have the same heathkit tr checker
it just a different colour. i got mine for $1 at ham club swap meet. i also have a radio shack tr tester that uses the transistor in an oscillator to light a neon bulb. it gives a crude relative gain estimate

p

#691

That looks like a real winner Clay! What is the battery compliment inside or does it have AC power, fporgot to look?

I just finished building a transformer tester with a Russian transistor, and it will do 900V @1V and 30 mA, yes interesting devices. Their low forward drop should have some definite advantages in some area??

Will be post picks of the "Octopus" shortly.

Geo

Show quoted text

From: "freshndaire" <fanman@...>
To: "CDV700CLUB" <[email protected]>
Sent: Monday, May 23, 2022 5:55:23 PM
Subject: Re: [CDV700CLUB] CDV-700 Transformer Tester and other essential shop-made service tools

Does anyone here have a manual for a Lectrotech Model TT-250 In-Circuit Transistor Analyzer?? I have one that seems to have issues, and do not understand how it is supposed to be used.? I have had no luck finding a manual or schematic.? Even finding someone that has a working one and/or knows how to use it properly would be good.? Here’s the most info I have found on it: ?? There are picture on eBay of one or more of them.? It does transistors and diodes.? Mine seems to have auto-biasing issues, and the leakage currents may be inaccurate.? High and low Beta ranges don’t line up well.? The in-circuit test mode seems to have problems due to switches that need to be cleaned, but does work for Beta Checks.? I will have to tear into it at some point, but it wasn’t a cheap tester in its day so I’d like to get it tuned up and 100% working as it seems to have a lot of potential.

I have been testing some Germanium transistors and getting “interesting” results with my Multi-Function Tester-TC1.? I’ll post the data after I get it all entered.

?

Clay Scott

?

From: [email protected] [mailto:[email protected]] On Behalf Of peter via groups.io
Sent: Monday, May 23, 2022 2:20 PM
To: [email protected]
Subject: Re: [CDV700CLUB] CDV-700 Transformer Tester and other essential shop-made service tools

?

geo

i have the same heathkit tr checker
it just a different colour. i got mine for $1 at ham club swap meet. i also have a radio shack tr tester that uses the transistor in an oscillator to light a neon bulb. it gives a crude relative gain estimate

p

#692

开云体育

It’s line powered.? It’s in decent shape, I am going to have to open it up and take a look.

?

Clay

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of Geo Dowell
Sent: Monday, May 23, 2022 7:02 PM
To: CDV700CLUB
Subject: Re: [CDV700CLUB] CDV-700 Transformer Tester and other essential shop-made service tools

?

That looks like a real winner Clay! What is the battery compliment inside or does it have AC power, fporgot to look?

?

I just finished building a transformer tester with a Russian transistor, and it will do 900V @1V and 30 mA, yes interesting devices. Their low forward drop should have some definite advantages in some area??

?

Will be post picks of the "Octopus" shortly.

?

Geo

?

From: "freshndaire" <fanman@...>
To: "CDV700CLUB" <[email protected]>
Sent: Monday, May 23, 2022 5:55:23 PM
Subject: Re: [CDV700CLUB] CDV-700 Transformer Tester and other essential shop-made service tools

?

Does anyone here have a manual for a Lectrotech Model TT-250 In-Circuit Transistor Analyzer?? I have one that seems to have issues, and do not understand how it is supposed to be used.? I have had no luck finding a manual or schematic.? Even finding someone that has a working one and/or knows how to use it properly would be good.? Here’s the most info I have found on it: ?? There are picture on eBay of one or more of them.? It does transistors and diodes.? Mine seems to have auto-biasing issues, and the leakage currents may be inaccurate.? High and low Beta ranges don’t line up well.? The in-circuit test mode seems to have problems due to switches that need to be cleaned, but does work for Beta Checks.? I will have to tear into it at some point, but it wasn’t a cheap tester in its day so I’d like to get it tuned up and 100% working as it seems to have a lot of potential.

I have been testing some Germanium transistors and getting “interesting” results with my Multi-Function Tester-TC1.? I’ll post the data after I get it all entered.

?

Clay Scott

?

From: [email protected] [mailto:[email protected]] On Behalf Of peter via groups.io
Sent: Monday, May 23, 2022 2:20 PM
To: [email protected]
Subject: Re: [CDV700CLUB] CDV-700 Transformer Tester and other essential shop-made service tools

?

geo

i have the same heathkit tr checker
it just a different colour. i got mine for $1 at ham club swap meet. i also have a radio shack tr tester that uses the transistor in an oscillator to light a neon bulb. it gives a crude relative gain estimate

p

?

#693

This evening's project added the next important tester I call the "Octopus" (see if you can figure out why?)

It's a straight clone of the ENi on my version of perfboard.

There are 6 wires with clips on the end, corresponding to the 6 terminals on Eni etc. transformers. With it I can now test ENi etc. HV transformers without endangering a CDV700 board at all. It uses the Russian transistor, the first time I ever used one.

Note to Michael C- the first one tested was one you sent me with 3 wires on each side, it works well. As a matter of fact, it was putting out 900V even with the input DC turned down to 1V, and only drawing 30mA to boot,

Pics of the beast attached.

Geo

PS it took longer than expected, I had some of that one band high wattage resistors in backwards.

Flying transformer tested.jpg

Flying transformer tested.jpg

Still-Working_at_1V.jpg

30mA_at_1V_in_916V_out_amazing.jpg

Used_to_Test-Primary_side_Zener_regulator.jpg

916V_on_Ludlum_500_1V_in_at_30mA.jpg

#694

开云体育

Hi Geo,

? This is an interesting coincidence you bring this up at this time.? I was using my cheap Mulitifunction tester-TC1 (available for less than $20 with free shipping on eBay) to test some transistors.? For those that may not have not seem my earlier post, they determine the type of part, display a schematic symbol allowing you to determine what pin is what, and display measurements of the parameters it chooses for the part identified.? Pretty cool for a <$20 instrument.? The downside is you have no idea how it performs the determination and test and sometimes that is important.

? The transistors I am testing were made available by one of the Geiger groups members a few years back.? They are Black Philco 2N1499A PNP Germanium transistors, I have 15 of them.? The date codes is 6237 on all of them so they are pretty close to 60 years old.? I tested them with the TC1 with an interesting and puzzling result.? They all were determined by the unit to be transistors (ie: no failed parts).? However, 7 of them came up with an alternate component symbol that is a PNP transistor with a C-E connected “damper” diode (Anode to C, cathode to E).? I had never run into that discrepancy before, but have mostly tested silicon transistors.? The diode detection seemed repeatable but there does seem to be something that can change it, it looks like it is DUT temperature.?

??Below is a list of the data for the parts per my TC1.? I noticed a substantial change in Iceo (ie: leakage) between the first and subsequent tests on some of the devices so I ran the test 10 times and recorded the data again.? I thought Iceo may be increasing as the die temp goes up for each test, but the data doesn’t seem to reflect that.? I would have to do more testing and I don’t want to do that right now.? Another anomaly is that ?on some parts it displays Ices- the collector to emitter leakage with base shorted to emitter.? Since there is no way to know what would enable/disable testing that parameter, it is a mystery.? The different collector currents (Ic) are interesting as well.

? This isn’t very useful because I thought I could get some info from the Lectrotech, but that didn’t work out.? If you have some of these transistors it might be interesting to see it.

?

- Means the tester did not test the parameter.

(10) is the data after 10 tests were completed.? Data for #1 - #3 was run after all other data was entered since I didn’t catch the changes until #4.

?

Trans# hfe???????? Vbe(mV)???????????? Ic(mA)? Iceo(uA)????????????? Ices(uA)?????????????? diode

1????????????? 159???????? 222???????????????????????? 1.6????????? 37?????????????????????????? -????????????? ??????????????? no

1 (10)???? 170???????? 223???????????????????????? 1.8????????? 61?????????????????????????? -????????????????????????????? no

2????????????? 84?????????? 292???????????????????????? 6.6????????? 14?????????????????????????? -????????????? ??????????????? no

2 (10)???? 78?????????? 286???????????????????????? 6.6????????? 8????????????????????????????????????????????????????????????? no

3????????????? 182???????? 210???????????????????????? 1.9????????? 80?????????? ??????????????? -????????????? ??????????????? no

3 (10)???? 160???????? 209???????? ??????????????? 1.7????????? 69?????????????????????????? -????????????? ??????????????? no

4????????????? 221???????? 204???????? ??????????????? 2.3????????? 100???????? ??????????????? -????????????? ??????????????? no??????????

4 (10)???? 201???????? 209???????????????????????? 2.1????????? 58?????????????????????????? ??????????????? -????????????? ??????????????? no?????????? Noticed leakage drops between subsequent tests????????????

5????????????? 77?????????? 272???????????????????????? 6.6????????? 8????????????? ??????????????? -????????????? ??????????????? no

5 (10)???? 75?????????? 277???????? ??????????????? 6.6????????? 5????????????????????????????? -????????????? ??????????????? no

6????????????? 166???????? 223???????????????????????? 1.7????????? 120???????????????????????? -????????????? ??????????????? no

6 (10)???? 153???????? 223???????? ??????????????? 1.6????????? 68?????????????????????????? -????????????? ??????????????? no

7????????????? 48?????????? 255???????? ??????????????? 6.6????????? 50?????????? ??????????????? 17?????????? ??????????????? no

7 (10)???? 46?????????? 265???????????????????????? 6.6????????? 32?????????? ??????????????? 14?????????? ??????????????? no?????????? 1st time Ices showed up on tester

8????????????? 69?????????? 288???????? ??????????????? 6.6????????? 14?????????????????????????? -????????????? ??????????????? 4.31V

8 (10)???? 72?????????? 298???????? ??????????????? 6.6????????? 7????????????????????????????? -????????????????????????????? 4.4V? ???? Heated the part and Iceo increased to 120 and Ices showed up at 4.? Iceo goes up with increases in temp.

9????????????? 38?????????? 282???????? ??????????????? 6.5????????? 10?????????????????????????? -????????????????????????????? no

9 (10)???? 37?????????? 282???????? ??????????????? 6.5????????? 7????????????? ??????????????? -????????????????????????????? no

10?????????? 51?????????? 284???????? ??????????????? 6.6????????? 7????????????????????????????? -????????????????????????????? 4.18V

10 (10)? 49?????????? 287???????? ??????????????? 6.5????????? 4????????????? ??????????????? -????????????????????????????? 4.26V

11?????????? 54?????????? 269???????????????????????? 6.6????????? 21?????????????????????????? -????????????????????????????? 4.41V

11 (10)? 52?????????? 275???????? ??????????????? 6.6????????? 12?????????????????????????? -????????????????????????????? 4.4V

12?????????? 465???????? 223???????? ??????????????? 5.7????????? 920???????? ??????????????? 1????????????????????????????? no? ???????? This tested as having the diode earlier.

12 (10)? 488???????? 229???????????????????????? 5.6????????? 780???????????????????????? -????????????????????????????? no??????????

13?????????? 76?????????? 278???????? ??????????????? 6.6????????? 8????????????????????????????? -????????????????????????????? 4.05V

13 (10)? 71?????????? 281???????????????????????? 6.6????????? 5????????????????????????????? -????????????????????????????? 4.07V

14? ???????? 40?????????? 267???????? ??????????????? 6.5????????? 8????????????????????????????? -????????????????????????????? 4.19V

14 (10)? 36?????????? 282???????????????????????? 6.5????????? 2????????????? ??????????????? -????????????????????????????? 4.19V

15?????????? 27?????????? 298???????????????????????? 6.4????????? 1????????????????????????????? -????????????????????????????? 4.24V

15 (10)? 24?????????? 304???????????????????????? 6.4????????? -????????????????????????????? -????????????????????????????? 4.28V

?

My conclusion at this time is the TC1 is okay as a transistor tester but without a known good tester to compare it to it I can’t determine the accuracy of the hfe measurements.? They seem

#695

hey George, that is cool.? ?Glad the transformer is working.? Actually helps me knowing that - hone my trouble shooting skills and focus more on the other parts of the circuit.? ?and I want to understand more about transformers especially multiple windings.??

#696

Where did those come from Michael?

You mentioned before but I forgot.

Geo

Show quoted text

From: "Michael" <mtcooper01@...>
To: "CDV700CLUB" <[email protected]>
Sent: Monday, May 23, 2022 10:28:12 PM
Subject: Re: [CDV700CLUB] CDV-700 Transformer Tester and other essential shop-made service tools

hey George, that is cool.? ?Glad the transformer is working.? Actually helps me knowing that - hone my trouble shooting skills and focus more on the other parts of the circuit.? ?and I want to understand more about transformers especially multiple windings.??

#697

the 3 wire each side was the original on the ENi.?

the transformer on the board with the multicolored wires I got from Lenox 2 years ago.?

the other transformer 4 wires one side 2 the other, bought off ebay "flyback transformer".? ?

#698

开云体育

Nice work, Geo!

I thought of making a similar test jig myself but time is a rare commodity these days.?

Well done!

AlanJ

Show quoted text

On May 23, 2022, at 11:43 PM, Michael C <mtcooper01@...> wrote:

the 3 wire each side was the original on the ENi.?

the transformer on the board with the multicolored wires I got from Lenox 2 years ago.?

the other transformer 4 wires one side 2 the other, bought off ebay "flyback transformer".? ?

#701

Testing done on the first of these, haven't found the 4 wire/2 wire one yet, but hey, I cleaned up my bench over the weekend, I can't find anything!

ENi transformer on the Octopus transformer tester- perfect in all respects. Producing way more HV to turn on the Zedner regulator I added to the tester this morning at 908V DC.

Color wire transformer- here's where the Octopus come in handy. We can guess the pairs of winding by using an Ohmmeter, to check their DCD resistance, one is normally 5 Ohms, the other more but not a lot, but enough to identify, and the HV one is always way higher than the other two. What we don't know is the polarity of each winding. These HV generators nee the polarity just right on all 3 windings or nada. Try that with a power transformer, you get an explosion! Once I got the polarities all in line this transformer also produced HV output, but below the level required to activate the Zeners. By reading it's in the 850V range. Probably good for most GC work, but we really need the regulator online to get the best performance. This is at 3V. I can and will try higher, but that's not the point, I think.

Next I'll scare up the 4/2 wire job.

Geo

#702

Update on the missing transformer. No wonder I couldn't find it Michael, you had cleverly hidden it in a clear plastic bag marked "eBay Transformer".

But find it I did, bad new I couldn't get it to oscillate on the ENi HV circuit clone, and tried every combination of polarities. That can be confusing tho, have you had any luck with it before?

Geo

Show quoted text

From: "geoelectronics at rallstech.net" <GEOelectronics@...>
To: "CDV700CLUB" <[email protected]>
Sent: Tuesday, May 24, 2022 11:04:47 AM
Subject: Re: [CDV700CLUB] CDV-700 Transformer Tester and other essential shop-made service tools

Testing done on the first of these, haven't found the 4 wire/2 wire one yet, but hey, I cleaned up my bench over the weekend, I can't find anything!

ENi transformer on the Octopus transformer tester- perfect in all respects. Producing way more HV to turn on the Zedner regulator I added to the tester this morning at 908V DC.

Color wire transformer- here's where the Octopus come in handy. We can guess the pairs of winding by using an Ohmmeter, to check their DCD resistance, one is normally 5 Ohms, the other more but not a lot, but enough to identify, and the HV one is always way higher than the other two. What we don't know is the polarity of each winding. These HV generators nee the polarity just right on all 3 windings or nada. Try that with a power transformer, you get an explosion! Once I got the polarities all in line this transformer also produced HV output, but below the level required to activate the Zeners. By reading it's in the 850V range. Probably good for most GC work, but we really need the regulator online to get the best performance. This is at 3V. I can and will try higher, but that's not the point, I think.

Next I'll scare up the 4/2 wire job.

Geo

#703

开云体育

no, never got the 4-2 to work.? interesting

From: [email protected] <[email protected]> on behalf of Geo Dowell <GEOelectronics@...>
Sent: Tuesday, May 24, 2022 9:24 AM
To: CDV700CLUB <[email protected]>
Subject: Re: [CDV700CLUB] CDV-700 Transformer Tester and other essential shop-made service tools

?

Update on the missing transformer. No wonder I couldn't find it Michael, you had cleverly hidden it in a clear plastic bag marked "eBay Transformer".

But find it I did, bad new I couldn't get it to oscillate on the ENi HV circuit clone, and tried every combination of polarities. That can be confusing tho, have you had any luck with it before?

Geo

Show quoted text

From: "geoelectronics at rallstech.net" <GEOelectronics@...>
To: "CDV700CLUB" <[email protected]>
Sent: Tuesday, May 24, 2022 11:04:47 AM
Subject: Re: [CDV700CLUB] CDV-700 Transformer Tester and other essential shop-made service tools

Testing done on the first of these, haven't found the 4 wire/2 wire one yet, but hey, I cleaned up my bench over the weekend, I can't find anything!

ENi transformer on the Octopus transformer tester- perfect in all respects. Producing way more HV to turn on the Zedner regulator I added to the tester this morning at 908V DC.

Color wire transformer- here's where the Octopus come in handy. We can guess the pairs of winding by using an Ohmmeter, to check their DCD resistance, one is normally 5 Ohms, the other more but not a lot, but enough to identify, and the HV one is always way higher than the other two. What we don't know is the polarity of each winding. These HV generators nee the polarity just right on all 3 windings or nada. Try that with a power transformer, you get an explosion! Once I got the polarities all in line this transformer also produced HV output, but below the level required to activate the Zeners. By reading it's in the 850V range. Probably good for most GC work, but we really need the regulator online to get the best performance. This is at 3V. I can and will try higher, but that's not the point, I think.

Next I'll scare up the 4/2 wire job.

Geo

#704
Edited

Michael, on the transformer theory, real basic stuff you know already- Voltage in-out is straightforward, it is directly proportional to the number of turns in the "primary" or" power applied winding " to the number of turns in the secondary or "power supplying" winding.?

If being used as an impedance matching transformer, that's a different story, and we can discuss that later of it ever comes up.

CDV-700 turns 3V DC pulses in to ~900V "AC" pulses, but not a sine wave.

The important part concerning the CDV-700 arrangement is the phasing. All transformer windings have a high and low phase relationship compared to the other windings. When stacking windings to get different Voltages, this must be strictly?adhered to.?

If you were using a transformer with one primary and two secondaries on sine wave AC, all the windings, including the primary,? wound in the same direction will have on terminal "High" while the other one is "Low". Just like a car battery is made up of individual cells in series, they must all be pointing in the same directionj to ADD their individual Voltages.
Any one in backwards will "SUBTRACT" it's Voltage. Batteries or cells in parallel must have all their "high" sides hooked together and all their low sides hookked together, otherwise, disaster.

Add a transitor driver to that mix and things get complicated. Transistors in CDV-700 HV and LV supplies are nothing more than switches, working exactly like the "points" in a car ignition. It is nothing more than a switch which turns itself on and off.

So polarity or phase? matter from that standpoint too. If the feedback winding were reversed, when feeding the transistor base the "shutoff" pulse, it would insteaqd turn on even more, not good.

CDV transformers have iron cores, those play an important part on the frequency of when it shut pff during each cycle.

All CDV manuals should have a detailed description of that sequence, and it happens around 100 time each second.

Geo