UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post - What are the chances of a modern LOPT failing?

TonyDuell · 4th Dec 2017, 7:43 pm

I've certainly had modern-ish line output transformers fail, not always in obvious ways. I had one go in an Amstrad monitor, the fault was in the thick film resistor unit used to set the focus and first anode voltages, with the result that these drifted as the thing warmed up. Back then (this was 25 years ago) I could get a genuine replaement from (I think) CPC. Not cheap though.

I've replaced many line output transformers (well the manual called them 'flyback transformers, but that's the American term) in DEC terminals. VT100s etc would eat transformers if some of the diodes or capacitors on the video board went leaky, which they did with monotonous regularity. VT220s were better, but the VT3xx series had major line output issues in my experience. No idea what I'd do if I needed one now...

The fact that Konig, HR Dieman, etc sold 'copies' of the line output transformers for popular TVs and monitors would suggest there was a market for them. And thus that said
transformers did fail.

4th Dec 2017, 7:43 pm	#22
TonyDuell Dekatron Join Date: Jun 2015 Location: Biggin Hill, London, UK. Posts: 5,215	Re: What are the chances of a modern LOPT failing? I've certainly had modern-ish line output transformers fail, not always in obvious ways. I had one go in an Amstrad monitor, the fault was in the thick film resistor unit used to set the focus and first anode voltages, with the result that these drifted as the thing warmed up. Back then (this was 25 years ago) I could get a genuine replaement from (I think) CPC. Not cheap though. I've replaced many line output transformers (well the manual called them 'flyback transformers, but that's the American term) in DEC terminals. VT100s etc would eat transformers if some of the diodes or capacitors on the video board went leaky, which they did with monotonous regularity. VT220s were better, but the VT3xx series had major line output issues in my experience. No idea what I'd do if I needed one now... The fact that Konig, HR Dieman, etc sold 'copies' of the line output transformers for popular TVs and monitors would suggest there was a market for them. And thus that said transformers did fail.