Cossor 565 only started because it should take an hour

[Cobaltblue]

I have not done many restorations lately (3 years) due to work comitments and house rebuilding. I have a number of incomplete projects.

I dipped my toe a few weeks back with a Cossor CR1101U a Philips in disguise.

I never wanted to restore it it was too far gone I just wanted to do basic repairs to asses the major components but it was awful so many tracks missing poor repairs and open circuit valve holders in the end I stopped wasting my time and scrapped it keeping the parts I wanted valves, output transformer dropper resistor etc.

Fast forward to Wednesday and whilst trying to clear one of my stores a 565 appeared minus most of the valves and looking scruffy.

These are truly horrible sets IMHO flimsy bent wood cabinets an even flimsier PCB and an absolutely minimum component count yet once working they work amazingly well and sound not at all bad .........very depressing!

So the valves were still on the bench from the CR1101U and as they are the same types that saved me boxing and storing those!

This set has a lot of Hunts mouldseals so those will need to go but on powering up no heaters having ruled out the on/off switch with its pre-blown Hunts modulation hum cap the dropper had 2 open circuit sections.

The CR1101U had very similar dropper although twice the size. The dropper is held onto the pcb with a metal expanding clip.

the internal diameter of the two dropper resistors was the same so I was able to affix it although it will make refitting the pcb attachment a little more difficult.

I had heaters I was connected via limiter and had not yet snipped the grid coupling cap I wanted to see if there was life.

LW yes noisy hummy but no MW.

The wire to the MW coil was broken at the beginning of the winding.

It's Litz wire, I managed to pull the end of the winding out about 10mm and separate the cores the soldering iron would not burn off the enamel (not uncommon sets of this age) so I had to scrape the strands best I could with a modelling knife.

Rejoined the windings and using a quick drying varnish held the winding in place.

Quick check and MW now working.

Snipped the grid coupling cap and checked all the main voltages which were pretty much bang on, very little hum and no warming of the res/smoother cap.

Time to start changing some of those mouldseals.

Now which box are those poly caps in

So that was 2 hours I will never get back.

Cheers

Mike T

[kestrelmusic]

Originally Posted by Cobaltblue

So that was 2 hours I will never get back.

Mike T

Ah, yes, but what a lovely couple of hours! I confess I have never grudged the time spent in the workshop, even when many hours are spent tracing some elusive intermittent fault.

[Cobaltblue]

I normally enjoy working on sets I just don't get much joy from working on valve sets of this period.

They are terribly cheaply put together down to a price.

Due to the valves being at an advanced stage of development as well as other components whey work really well.

The early PCB's were also not that good although having said that this one survived a lot better than the contemporary Philips with its very cheap valve holders and unnecessarily thin tracks and small pads.

I will feel better about it once I find the boxes of new components and get this ready for cabinet repairs.

Cossor sets of this period are thin on the ground.

Cheers

MIke T