Ferguson FV37H PSU Issue

[IKC2E51R8]

Hi All,

A few years ago I bought a Ferguson FV37H (HR-D830 Deck) on eBay in practically new condition, came with the original box, manual., remote and even the polystyrene protection, it was sold with a fault that randomly it would stop playing and eject the tape which it did do on testing it when i got it, i put it away in the attic for attention a different time.

Finally took it out of the attic yesterday and plugged it in...nothing, dead not a sqeek not a light nothing, figured maybe the fuse just let go from sitting for so long (however unlikely it may be) took the top off and the fuse was fine...

I checked the PSU output voltages and they are all wrong (low) +45v alternates between 21v and the highest its been is 30v, the +12v is 8.1- 9.6v and the +5v is sitting around 3.9 - 4.6v, I changed a few parts that looked like they may have seen better days and same results....

Then i figured just to rule it out i resoldered the whole PSU board, plugged in and the unit came on as normal, display lit up and deck functions, however after about 2 mins the display faded and then dead.

about an hour ago i blew some hot air using a hair dryer around the secondary of the PSU and the unit came on, i fully expected it to die out again after a few mins when it begins to cool however ive had it playing a tape for the last 42 mins (according to the counter) and it seems to be running fine, the display and deck seem to be working perfect.

Anyone any ideas what might be causing this? I've attached the power supply diagram below which may help.

[ben]

If it's the generation I'm thinking of, change ALL the electrolytic caps in the PSU. Don't bother testing them. They gave rise to odd faults.

[jayceebee]

C17 was the usual cause back in the day.

John.

[IKC2E51R8]

I had thought C17 might be it so i already replaced it but same result.

I was hoping not to have to change all the electrolytic's only because i dont have all the values i need.

the machine stayed on for the whole film that played, i unplugged it and plugged it back in after 5 mins and it was dead again, blew some more hot air on it and it came back on. One thing i did notice though is the VFD is not as bright as i remember it being as it was when i first got it.

[ben]

Don't nurse this along, you'll end up with a blown PSU. What more proof do you need that those caps are duff? Replace with decent 105º types - not just any old junk - and you should have a reliable unit.

[Welsh Anorak]

I agree with Ben - change them now as if and when these PSUs blow up it's not a repair job you'll enjoy doing - and you'll need to change the caps anyway.

CPC is your best bet IMHO - they have a good range of Panasonic electrolytics and sell most singly, but do make sure they're 105 degree parts. Don't go for Mulicomp (RS Pro) as they are cheap and nasty. In my opinion, obviously!

[Sideband]

Originally Posted by ben

Don't nurse this along, you'll end up with a blown PSU. What more proof do you need that those caps are duff? Replace with decent 105º types - not just any old junk - and you should have a reliable unit.

Couldn't have put it better myself!! Don't mess with SMPS....decent caps will save more problems later. Low ESR types are a must from a decent supplier.

It might be worth just quickly checking R2 and R3 as well, the start-up resistors both 330K in case they've drifted high. Probably unlikely but while the power supply is out, you may as well check them.

[Sideband]

Originally Posted by IKC2E51R8

One thing i did notice though is the VFD is not as bright as i remember it being as it was when i first got it.

That's probably due to the -28V supply being low. That provides the bias to the VFD so again good quality caps should cure that.

[Nickthedentist]

Even 20 years ago, I used to change all the caps in these PSUs as a matter of course. Most pavement-find machines then worked straight away.

[Sideband]

Even good quality low ESR caps are relatively cheap and if you can buy the required values singly rather than in multiple packs, the total repair should be even cheaper. Believe us when we say that replacing all the electrolytics WITH GOOD QUALITY LOW ESR types will save tears later. SMPS require low ESR types because of the frequencies they work at (typically 30 to 80kHz). The power supply is likely to fail big time if wrong parts are used....probably taking most of the silicon out....

[williamsunique]

This used to be a common problem with these later models that use a switch mode power supply. The customer would go on holiday and switch everything off in the house. On their return the video would be turned back on and it would be dead. On the primary side of the power supply there was a 1uF 400 volt capaciter that failed. Nine out of ten times this was all that was required to restore working conditions. Very rarely though there was a lot more damage, which required the video to be returned to the workshop. The electrolytic capaciters on the secondary side also give trouble. Some circuits had two capacitors in the primary side. To be safe I would change all the electrolytics.

Paul.

[IKC2E51R8]

I changed all the electrolytics bar one which I didn't have but the ones I've changed have seemingly corrected the problem, unit comes on straight away now with display at normal brightness and the deck is functioning properly. I suspect the main culprits were C25 which was in the early stages of beginning to leak and C22 which was ever so slightly beginning to bulge, I missed that when I was initially looking over the power supply as it kind of hides between two heat sinks so it wasn't easily visible.

Thanks for all the help, this unit is saved from the grave now, I'm not particularly attached to it so I was very close to just scrapping it but now that it's working I cant justify scrapping a perfectly good machine.