High pitched sound from my Olivetti's CRT display. - UK Vintage Radio Repair and Restoration Discussion Forum

johnpriceuk · 11th Jan 2016, 8:00 pm

I bought this Olivetti Prodest PC-1 only two nights ago when it was demonstrated working to me. I have since got it home and connected it up only to discover that the CRT will not display a picture and is omitting a high pitched sound.

See this video for a demonstration of the problem
https://www.youtube.com/watch?v=_bTh-5-2wy0
The camera I used places its own high pitched sound in the recording but the sound I'm referring to is the one which can be heard when I switch the machine on.

Any ideas? I really just want to know if it sounds repairable because there is a TV repair shop near me which has been around for years and will hopefully still have the skills to repair something like this.

Really annoying and upsetting that it was literally working perfectly two nights ago and now it is suddenly doing this

SiriusHardware · 11th Jan 2016, 9:41 pm

Not sure what level of electronics you have yourself?

The sequence
-Unit Working
-Unit Travelled
-Unit Not working

...Leads me to hope that something just got bounced loose, or that a solder joint, perhaps on one of the legs of the Line Output Transformer or some other heavy PCB mounted component, got cracked during the journey. If you smack the side of the monitor (not too hard, just with the flat of your hand) does it flicker or does the sound change?

There is a page with some useful information about the Prodest here:

http://www.seasip.info/VintagePC/pro...1.html#display

On that same site, info about the wiring of the video output port, which might enable you to test the computer independently of the monitor by wiring it to any TV or video monitor with a Composite / 'AV in' input.

http://www.seasip.info/VintagePC/pc1pinouts.html#video1

johnpriceuk · 11th Jan 2016, 10:25 pm

I'm not too bad with a soldering iron but I've never messed around inside a CRT before and I'm a bit nervous about the high voltages and possibly causing more damage than I've fixed. Your advice is re-assuring however, and I'll take it down to the TV repair shop tomorrow and see what they can do for me.

The smack test does nothing!

I will try to wire up a SCART connector this week so at least I can use the computer for the time being

Thanks for your help.

11th Jan 2016, 8:00 pm	#1
johnpriceuk Retired Dormant Member Join Date: Nov 2014 Location: Liverpool, Merseyside, UK. Posts: 25	High pitched sound from my Olivetti's CRT display. I bought this Olivetti Prodest PC-1 only two nights ago when it was demonstrated working to me. I have since got it home and connected it up only to discover that the CRT will not display a picture and is omitting a high pitched sound. See this video for a demonstration of the problem https://www.youtube.com/watch?v=_bTh-5-2wy0 The camera I used places its own high pitched sound in the recording but the sound I'm referring to is the one which can be heard when I switch the machine on. Any ideas? I really just want to know if it sounds repairable because there is a TV repair shop near me which has been around for years and will hopefully still have the skills to repair something like this. Really annoying and upsetting that it was literally working perfectly two nights ago and now it is suddenly doing this

11th Jan 2016, 9:41 pm	#2
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,546	Re: High pitched sound from my Olivetti's CRT display. Not sure what level of electronics you have yourself? The sequence -Unit Working -Unit Travelled -Unit Not working ...Leads me to hope that something just got bounced loose, or that a solder joint, perhaps on one of the legs of the Line Output Transformer or some other heavy PCB mounted component, got cracked during the journey. If you smack the side of the monitor (not too hard, just with the flat of your hand) does it flicker or does the sound change? There is a page with some useful information about the Prodest here: http://www.seasip.info/VintagePC/pro...1.html#display On that same site, info about the wiring of the video output port, which might enable you to test the computer independently of the monitor by wiring it to any TV or video monitor with a Composite / 'AV in' input. http://www.seasip.info/VintagePC/pc1pinouts.html#video1

11th Jan 2016, 10:25 pm	#3
johnpriceuk Retired Dormant Member Join Date: Nov 2014 Location: Liverpool, Merseyside, UK. Posts: 25	Re: High pitched sound from my Olivetti's CRT display. I'm not too bad with a soldering iron but I've never messed around inside a CRT before and I'm a bit nervous about the high voltages and possibly causing more damage than I've fixed. Your advice is re-assuring however, and I'll take it down to the TV repair shop tomorrow and see what they can do for me. The smack test does nothing! I will try to wire up a SCART connector this week so at least I can use the computer for the time being Thanks for your help.