• Please review our updated Terms and Rules here

Phillips 8833/05G

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
43,953
Location
Pacific Northwest, USA
It's far less common for a flyback transformer to fail due to an open winding that it is for one to fail from a shorted one. I suggest that you double-check your work.
 

Gary C

Veteran Member
Joined
May 26, 2018
Messages
2,201
Location
Lancashire, UK
Checked again and

Meter on 2k Ohms range - Check
Meter working - Check
Measure from 1 to 5 - heater circuit as a simple one to test - 1MOhm, ie open circuit
Measure from 6 to 10 - Open circuit (drawing is in error, its not 18)

Seems to have had a catastrophic failure. Thinking HO Trans has been on too long ?
 

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
43,953
Location
Pacific Northwest, USA
Or you're probing the wrong pins. Do the "probe on one pin and the other probe on every other pin" dance. Could be that a change in the design was done and a different FBT was used.
 

Gary C

Veteran Member
Joined
May 26, 2018
Messages
2,201
Location
Lancashire, UK
Not that low though ?

Ypu may be right but other flybacks ki have xhecked are in the 2 ohm range not milliohm.

But a little distracted today putting a zuluscsi in an a2000
 
Last edited:

Gary C

Veteran Member
Joined
May 26, 2018
Messages
2,201
Location
Lancashire, UK
You were right Chuck. Flyback was fine except that someone had previously changed it for one that was not quite perfect and the earth connection is a bit of a bodge and is soldered to the LOPT so when it had been soldered into the board, it had desoldered the other end so no earth & no flyback.

Soldered properly and now working (though, oddly slightly rotated)
 

Gary C

Veteran Member
Joined
May 26, 2018
Messages
2,201
Location
Lancashire, UK
Oh, yes, I know and its done

Just odd that it was out as the clamp & the yoke's glue remained undisturbed. Must have given it a knock.
 

Gary C

Veteran Member
Joined
May 26, 2018
Messages
2,201
Location
Lancashire, UK
Quick (and stupid) question

When Donberg show a picture such as this one, the components connected to pins 5 & 3 are examples of expected external circuitry ? (unlike the diodes in the HV section)

Daft question probably but I am getting 24 ohm between pin 10 & pin 5 (its another Philips 8833) and I just want to be certain before I order one.

Flyback.png
 

Chuck(G)

25k Member
Joined
Jan 11, 2007
Messages
43,953
Location
Pacific Northwest, USA
3 and 5 components are external, yes. For a clue, look where the terminal numbers are placed. Note that for the focus and screen pots, as well as the diode appear before the pin 11 notation, so internal. For 3 and 5, the components are after the pin numbers, so external. 24 ohms between 10 and 5 would seem to indicate a shorted winding.
 

Gary C

Veteran Member
Joined
May 26, 2018
Messages
2,201
Location
Lancashire, UK
So new flyback received from donberg and it explains some things

The earth pin does not align with the hole in the circuit board and as received is bent flat. Now recently I got another 8833 in for maintenance that had had a flyback replacement but 'it had failed straightaway'. This one had a wire solded to the ground pin and into the hole and I suspect then when soldering one end into the board, the other end had become unsoldered. Took it out to test and the wire fell off. Soldered back in carefully and the monitor sprang into life

Its a bit of a poor arrangement but I have effectively 'surface mounted' the bent pin
 
Top