Rare find! A Magnavox Brittany tv!

[Yamamaya42]

been looking weekly, they seem to be out of compatible ones.

[Yamamaya42]

I will post pics and resistance readings of all 3 flybacks tonight, the OEM (with the corroded eyelets ) , fried HVO-5 and RAM X032.

[Yamamaya42]

OK
first the OEM
that was in BAD shape, you can see the corroded wires and contacts, which prompted me to replace it.

http://suzaku.live-evil.org/0605251956.jpg

readings

1-2 39.5 ohms
2-3 23 ohms
6-5 0.6 ohms
5-4 6.9 ohms

the dead hvo-5
http://suzaku.live-evil.org/0605251957.jpg
it seems to have thinner wires than the OEM for 1-2, perhaps that;s why it burned?
readings.
1-2 1.8k OUCH!
2-3 40 OHMS
6-5 .0.6 ohms
5-4 6.8 ohms

http://suzaku.live-evil.org/0605251958.jpg
RAM 0x32
1-2 36 ohms
2-3 317 ohms not surprising since its a 13-14k, output.
5-4 0.6 ohms
5-4 6.4 ohms
5-7 9.3 ohms
one note. the heater for the HV rect has only one turn where the others have 2 , this will have to be changed.
with all this, I do think this will work, unless someone else sees something i have not.

[Alex KL-1]

More complicated will be the issue of proper matching with the yoke. They interact in final image width and linearity. Some are sensitive and affects the HV level due to dependence of the yoke load/resonance.

[Yamamaya42]

Originally Posted by Alex KL-1

More complicated will be the issue of proper matching with the yoke. They interact in final image width and linearity. Some are sensitive and affects the HV level due to dependence of the yoke load/resonance.

no problem!
the maggie yoke is 360330-7 which the RAM replacement is Y70F08, which is the one it says to use with this flyback, so it should be OK.

[Alex KL-1]

Originally Posted by Yamamaya42

no problem!
the maggie yoke is 360330-7 which the RAM replacement is Y70F08, which is the one it says to use with this flyback, so it should be OK.

Perfect!

[bandersen]

I would not add another loop for the HV rectifier filament. If there's enough power going though it to produce the proper deflection and HV, the filament voltage/current will be correct.
All the B&W rectifier tubes use the same filament power. 1.25v @ 0.2A.

[Yamamaya42]

Originally Posted by bandersen

I would not add another loop for the HV rectifier filament. If there's enough power going though it to produce the proper deflection and HV, the filament voltage/current will be correct.
All the B&W rectifier tubes use the same filament power. 1.25v @ 0.2A.

should i remove the 4.7 ohm resistor or leave it in line?

[bandersen]

Originally Posted by Yamamaya42

should i remove the 4.7 ohm resistor or leave it in line?

Always using an inline resistor for current limiting. Typically, they are 3.3 - 4.7 ohms.

[Yamamaya42]

Originally Posted by bandersen

Always using an inline resistor for current limiting. Typically, they are 3.3 - 4.7 ohms.

Tks,

I was not sure, as the paperwork that came with the RAM showing the "typical circuit" had no resistor, it also shows the damper plate hooked to P7 and yoke H to P4, but I will hook both to P4 in this case as it originally was wired OEM.

[bandersen]

Worst case you can use a solid state HV rectifier diode

[Yamamaya42]

Such as a NTE508...
thought of that.
tried one in my CTC 16XL and it went FOOM.

but this will be at much less voltage and load, perhaps it will hold up and w/o the heater, it's less load on things, just a wee bit.

[bandersen]

Rated for 45,000 volts and 110mA peak/5mA average current! No way it should have crapped out.

[Yamamaya42]

I agree, it should not have blown, but after 20 min of run time, the screen dimmed, and shrank horizontally, i shut down and it was burning hot to the touch, changed back to a glass 3CA3 and it's been OK for years.

Weird.

even stranger, the same thing happened to Shango when he tried one in a color RCA set, it lasted a bit longer, but it also got super hot and lost brightness ans shrank.

I just ordered on for this set, it will be running 10kv less at least, with no shunt loading it down, so it better not blow this time!

[bandersen]

I wonder if they are selenium rectifiers? Their internal resistance goes up over time and they start running warmer and warmer until poof!