The Mongrel

[Steve Anderson]

What are planning to use the ECH33 for? It's designed as an oscillator/mixer for radios. RF to IF conversion.

Likewise the 6AR7? Pentode + two signal diodes (AM detection and AGC).

The 6X5 is just an octal version of a 6X4, same limits/ratings.

True, it could well outgrow the size of the chassis you're planning to use...try and find smaller tubes...

Sorry Harry, I mis-read your posting previous...Ah! that's what that old radio used, not what you are planning to use, my mistake...

Steve A.

[Harry Dalek]

The DG7-32 I did for Hans was quite a few years ago, he did build it but only to a very rough stage, something distracted him and he had to stop. The deflection plates are AC-coupled (as are quite a few of your following scans/postings) as he only needed AC-coupling. For us using NBTV, SSTV, we need DC-coupling due to the low frequencies involved. SSTV has a vertical frequency of around 0.125Hz.

OH got ya now i was thinking it was thinking it could be this CRT just needs it this way ,no problems

The actual CRT part and deflection circuits are actually the easiest part of the whole thing. The hardest part is (rather surprisingly) is the power supply. CRTs, even simple ones like this one, require many different voltages. In the middle in terms of complexity are the video, sync separation and timebases...though they're not 'a piece of cake' either.

Well i do like the power supply part just need not to blow any thing up or get killed ! I Like working with higher voltages you have to always think ahead what are you doing be more careful , which is good way to think when working on any thing .

I wanted to start on the power supply with out this the rest does not come so any advice i will take on till i get it right !

[Harry Dalek]

What are planning to use the ECH33 for? It's designed as an oscillator/mixer for radios. RF to IF conversion.

Likewise the 6AR7? Pentode + two signal diodes (AM detection and AGC).

The 6X5 is just an octal version of a 6X4, same limits/ratings.

True, it could well outgrow the size of the chassis you're planning to use...try and find smaller tubes...

Steve A.

This list of 4 Vacuum tubes were the ones out of the old radio i scrapped the Transformer was driving i am using Steve

you can see the 4 in the tub in photo .i was thinking knowing what they were you would know what the transformer had to drive .

No i am not using those size Tubes i like the look of them but i can see it would be a tight fit if i was lucky .

[Steve Anderson]

Sorry Harry, I mis-read your posting previous...Ah! that's what that old radio used, not what you are planning to use, my mistake...it makes sense now...

Steve A.

From that list of tubes that transformer was designed to produce +250V @ 55mA, 6.3V @ 1.65A, about right for what it is...HT figures are approximate...total mains load, maybe 30W...

[Harry Dalek]

Sorry Harry, I mis-read your posting previous...Ah! that's what that old radio used, not what you are planning to use, my mistake...it makes sense now...

Steve A.

No problems

I had a look at my Big Transformer
I am not sure about sure about but needs testing which i did a little bit now, its massive it would just fit in the care but possible depends if it works

this is the top it helps

I am thinking the 0 110 0 110 110 10 20 bottom row is the mains primary the wiring looks like its going the centre of the transformer primary logical but the readings seem very low to me readings below little confusing but look at the bottom row voltages above
0 to 110 0 3.8ohm 0 to 2nd 110 7.6 ohm 0 to 10 7.9ohm 0 to 20 8.1 ohm


I am am thinking some thinking must still be working on this thing

[Steve Anderson]

The top-shot photo isn't that clear, get some good light, outside but not direct sunlight, and try again, a nice cloudy/overcast day being best - shouldn't be hard in Melbourne... KEEP THOSE PHOTOS. Then I hopefully can work out what is what. Then a clean-up session (but not yet) and resistance checking to confirm...do not apply power...looking at the time right now you may have to wait until tomorrow for some decent light..

It looks a much better candidate than the radio transformer, though we may have to use that as well...

I wonder what it came out of? Certainly some odd voltages (those I can see) but it looks much more useful...

Steve A.

[Harry Dalek]

The top-shot photo isn't that clear, get some good light, outside but not direct sunlight, and try again, a nice cloudy/overcast day being best - shouldn't be hard in Melbourne... KEEP THOSE PHOTOS. Then I hopefully can work out what is what. Then a clean-up session (but not yet) and resistance checking to confirm...do not apply power...looking at the time right now you may have to wait until tomorrow for some decent light..

It looks a much better candidate than the radio transformer, though we may have to use that as well...

I wonder what it came out of? Certainly some odd voltages (those I can see) but it looks much more useful...

Steve A.

Yes its a bit dark this afternoon i took a flash shot if that helps

Its the old 60s scope in fact it ran the Beast monitor CRT many tubes in that scope ,it died i was thinking it was this transformer primary but may be it was some thing else .
Perhaps one or more of the secondary windings are open checking the 6.3 to 6.3 i don't seem to be getting any thing resistance wise but not sure if i am checking across the right connections ,but makes sense why the tubes were not lighting up on switch on. lot of windings connected on the secondary and others do show resistance .
5 Amp Transformer by the looks of it .
If this gos no where i can get another valve transformer the supply is not endless but i have a few . least this is worth checking out first need to remove those wires so you can see covered voltage connections .

[Steve Anderson]

Much better, so here's a sketch of what I feel fairly sure of, the items in red need some clarification/updating...

Don't do anything to it for a while, tempted though you might be...clean up the terminals and remove the off-cuts, but leave the two links in my sketch in place...

Steve A.

Harry's Tube Display 1-Model.gif (8.24 KiB) Viewed 10212 times

[Harry Dalek]

Much better, so here's a sketch of what I feel fairly sure of, the items in red need some clarification/updating...

Don't do anything to it for a while, tempted though you might be...clean up the terminals and remove the off-cuts, but leave the two links in my sketch in place...

Steve A.

The attachment Harry's Tube Display 1-Model.gif is no longer available

No this one i am scared to power up to mains till i know for sure what is the primary just guessing at the moment

That's 9v 0 9V on the ? and others look all correct what's marked

A very confusing transformer resistance testing the only thing that looks like a mains connection to me is the middle row Ov 550v 700v from 0 here those 2 are 630 ohm and 810 ohm.....
i went looking for a schematic on the old oscilloscope the BWD421A when i was looking for its crt data now in the Beast monitor.
could not find the exact scope but it's similar to the Telequipment D43 manual schematic below ,i can see see its not 100% the same better than nothing

[Steve Anderson]

Right, here's my first guess as to what that transformer looks like as a schematic...

The next thing to do is measure the resistances R1 to R4 as shown, check they are connected to absolutely nothing else, all other terminals and the frame/chassis. Let me know what R1 to R4 are.

Steve A.

The ?1.5kV? is possibly referring to the insulation on that winding being rated for 1.5kV for the CRT heater, so I suggest we use it for such...

[Harry Dalek]

Right, here's my first guess as to what that transformer looks like as a schematic...

Harry's Tube Display 2-Model.gif

The next thing to do is measure the resistances R1 to R4 as shown, check they are connected to absolutely nothing else, all other terminals and the frame/chassis. Let me know what R1 to R4 are.

Steve A.

Thanks Steve !
I do need help with this Transformer , well the primary side is what i first expected it was so that's good and doing the readings again R1 is 3.8 ohm R2 7.6 ohm R3 7.9 ohm R4 8.1 that's very low to me i can only think the primary wire size is massive similar to a microwave transformer .

I suppose the next step if this sounds right is either check the secondary or power up the primary ? i have to admit with out your help i would not connect to mains but another HV transformer first and do a quick turn on off with the meter on one of the the secondary windings .
The Transformer schematic looks right on the primary side as it had a switch to change the different country mains voltages
With a primary this low in ohms i'd be pretty careful

[Steve Anderson]

DO NOT POWER IT UP YET...we're nowhere near finished yet...you can find out a lot more about transformers from resistance testing rather than voltage...

I've made assumptions, I'd rather confirm them first (or otherwise) before going further...

Steve A.

Sec. A, B, C and D should be very low resistance, basically unreadable on the average DVM, but just check they're not open-circuited or connected to any other secondary (or primary or earth/chassis)...i.e. Check A-B, then A-C, A-D and so on - including the primary and chassis/earth. Do the same with Sec, B, then C, then D.

[Harry Dalek]

DO NOT POWER IT UP YET...we're nowhere near finished yet...you can find out a lot more about transformers from resistance testing rather than voltage...

I've made assumptions, I'd rather confirm them first (or otherwise) before going further...

Steve A.

Don't worry i will leave it be ,till i hear from you what you think .

Sec. A, B, C and D should be very low resistance, basically unreadable on the average DVM, but just check they're not open-circuited or connected to any other secondary (or primary or earth/chassis)...

Ok Steve i can check again the other connections ,but pretty sure from yesterday 0 to 20 R1 to R4 did not connect any where else

[Steve Anderson]

Sec. A, B, C and D should be very low resistance, basically unreadable on the average DVM, but just check they're not open-circuited or connected to any other secondary (or primary or earth/chassis)...i.e. Check A-B, then A-C, A-D and so on - including the primary and chassis/earth. Do the same with Sec, B, then C, then D.

Then go through all other secondaries making notes of resistances of each winding or any shorts or differences from my schematic above. It's a tedious and boring task, but it should be done...let me know the outcome and resistance values you find...so we have no surprises later on...

Steve A.

[Harry Dalek]

Sec. A, B, C and D should be very low resistance, basically unreadable on the average DVM, but just check they're not open-circuited or connected to any other secondary (or primary or earth/chassis)...i.e. Check A-B, then A-C, A-D and so on - including the primary and chassis/earth. Do the same with Sec, B, then C, then D.

No earthing from the primary connections or any of the secondaries so that's good ! earth is just the casing

I am very impressed with you working out this transformers secondaries ! you nailed it i just checked with the meter .

Then go through all other secondaries making notes of resistances of each winding or any shorts or differences from my schematic above. It's a tedious and boring task, but it should be done...let me know the outcome and resistance values you find...so we have no surprises later on...

Steve A.

[/quote]

A 6.3 5A 8ohm

B 6.3 0>2A 8ohm

C 6.3 5A 8ohm

D 6.3 1.5A 8ohm

E 0 550V 649 Ohm

F 0 700 835 ohm

G 200v 50Ma 78 ohm

H 130v 30Ma 23 ohm

I,J 9V 0 9v 8 ohm 8ohm

K 200v 30 Ma 34.5 ohm

Whoops mistake with my lettering after 500v connection sorry