Sanyo VTC 5000 power unit - UK Vintage Radio Repair and Restoration Discussion Forum

spamfritter · 26th Jan 2022, 8:56 am

In parallel with wresting with a 5300 I also dug out a pair of VTC5000's that I have had hidden away since my house move 6 years ago. One I have cleaned up, re belted and tweaked up the idlers etc as per excellent info from previous posters on this site. Once I had understood that the way this rewinds / unlaces etc I realise it is working well and I am just waiting for a new idler assembly to appear from Australia to polish off the job. The second is a bit more fun. I re belted this and also the PSU was playing up so I changed all the capacitors to low ESR ones and all appeared to be going well. Left it on soak test but now the machine is dead . It looks like the fuse is OK but the magic smoke has escaped ! PSU now out on the bench and awaiting further inspection.

murphyv310 · 26th Jan 2022, 12:54 pm

Hi.
This is a good old linear power supply and generally very reliable. Regarding caps any that were changed in their service life were 105c rated and correct value. We never had an ESR meter in those days but just looked at the ripple on the scope. This was the deciding factor whether to replace or not.
I've heard that extremely low ESR rated caps can cause issues with surges in some power supplies, I can't say yae or nae though, I suppose it's possible. IMHO I always fit like for like whenever possible.

spamfritter · 17th May 2022, 2:36 pm

The first one sorted ! Couple of capacitors changed plus a full set of belts etc from Melbourne Australia (not joking) and it it operational. Plays my old pre recorded tapes well via the RF output and the analogue ports. All it needs now is a wipe over with a damp rag to clean it up and it will be put into my working kit rack.

Now I have to convince the second one to work which looks to be more of a problem.

26th Jan 2022, 8:56 am	#1
spamfritter Pentode Join Date: Jun 2013 Location: Braintree Essex UK. Posts: 217	Sanyo VTC 5000 power unit In parallel with wresting with a 5300 I also dug out a pair of VTC5000's that I have had hidden away since my house move 6 years ago. One I have cleaned up, re belted and tweaked up the idlers etc as per excellent info from previous posters on this site. Once I had understood that the way this rewinds / unlaces etc I realise it is working well and I am just waiting for a new idler assembly to appear from Australia to polish off the job. The second is a bit more fun. I re belted this and also the PSU was playing up so I changed all the capacitors to low ESR ones and all appeared to be going well. Left it on soak test but now the machine is dead . It looks like the fuse is OK but the magic smoke has escaped ! PSU now out on the bench and awaiting further inspection.

26th Jan 2022, 12:54 pm	#2
murphyv310 Dekatron Join Date: Sep 2006 Location: Kilmarnock, Ayrshire, UK. Posts: 5,422	Re: Sanyo VTC 5000 power unit Hi. This is a good old linear power supply and generally very reliable. Regarding caps any that were changed in their service life were 105c rated and correct value. We never had an ESR meter in those days but just looked at the ripple on the scope. This was the deciding factor whether to replace or not. I've heard that extremely low ESR rated caps can cause issues with surges in some power supplies, I can't say yae or nae though, I suppose it's possible. IMHO I always fit like for like whenever possible. __________________ Cheers, Trevor. MM0KJJ. RSGB, GQRP, WACRAL, K&LARC. Member

17th May 2022, 2:36 pm	#3
spamfritter Pentode Join Date: Jun 2013 Location: Braintree Essex UK. Posts: 217	Re: Sanyo VTC 5000 power unit The first one sorted ! Couple of capacitors changed plus a full set of belts etc from Melbourne Australia (not joking) and it it operational. Plays my old pre recorded tapes well via the RF output and the analogue ports. All it needs now is a wipe over with a damp rag to clean it up and it will be put into my working kit rack. Now I have to convince the second one to work which looks to be more of a problem.