emulatorII-list

I now have a working power supply - and some of the rectifier diodes were indeed past their best. I replaced Q103, all of the capacitors and power resistors last night, but found that the PSU still blew the fuse straight away. It would appear that some of the diodes were indeed past their best, of the four diodes on the mains input CR101 to CR104, two were closed circuit in both directions. Replacing those stopped the instant fuse blowing, but didn't give any output on J101.

This morning, I decided to replace the remaining transistors and the PSU now appears to be fully functional. I may still replace the diodes on the output side as the failure of CR101 to CR 104 has left me wondering how much longer they will last.

Some further testing on the PSU tonight, then onto the EII itself, which supposedly had a dead voice before the PSU failed.

Kevin


--- In emulatorII-list@...m, "kgslug2" <kevingibson952@...> wrote:
>
> Thanks Darren,
> 
> 1 Ohm was what I had thought, so confirmation is good. I'm still not sure about the power rating, but I'll go with 1/2 W.
> 
> I have uploaded a list of replacement parts for everything I can find - i.e. everything except the transformers and inductors. A couple of the diodes are no longer obtainable, but there will be modern replacements. All of the electrolytics are 105C and of a higher voltage rating than the originals. All except the mains side ones are low ESR.
> 
> I haven't yet decided how much I am going to replace. I have removed all capacitors and power resistors and found the base of C115 to be decidedly bulged. The rectifier diodes are probably past there best, so I may replace those too. I'll probably leave the feedback section alone as this won't have been stressed like the rest of the circuit.
> 
> Kevin
> 
> 
> --- In emulatorII-list@yahoogroups.com, Darren Blondin <dblondin@> wrote:
> >
> > R106 was a component that fried on my power supply. I found this quote  
> > from my tech in an email about it:
> > 
> > "Your original pic of R106 confirms what I was managing to read from  
> > the stripes, it is 1 ohm."
> > 
> > Would be good if someone else could confirm this but I'd go with that  
> > for now.
> > 
> > Darren
> > 
> > 
> > On Nov 25, 2012, at 8:49 PM, kgslug2 wrote:
> > 
> > > Please ignore my question on THR101. I didn't think that the  
> > > schematic gave any value for it but it does - it is a SG220  
> > > thermistor.
> > >
> > > I'd still like to know about R106 though.
> > >
> > > Once I've finished compiling it, I'll put a list of the replacement  
> > > capacitors and various other parts in the files section.
> > >
> > > Kevin
> > >
> > >
> >
>