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Old 21st Jan 2018, 9:46 pm   #1
Darrencambs
Triode
 
Join Date: Jan 2018
Location: Huntingdon, Cambridgeshire, UK.
Posts: 12
Default Blaupunkt Arkansas 43942 Restoration

Hello all,

I picked up an eBay bargain a couple of weeks ago. An Arkansas radiogram and Challenge radiogram for £26 in total (cost me more in petrol for the round trip from Huntingdon to Bradford to collect them).

The Challenge is beyond economic repair as it looks like it's been underwater - chassis rusted, chipboard cabinet disintegrating, legs fallen off; but the Arkansas looks to be in decent condition. The Challenge will be going down to the local tip (unless anyone here wants it for spares?), and I intend restoring the Arkansas.

I'm a novice at this, but have a reasonable understanding of electronics and a great deal of common sense around mains electricity. I've also done a great deal of reading of numerous posts on this website - so, thanks for all the help so far! I've got a copy of the schematic for a Granada 23400 which seems to be an identical chassis, albeit in a different cabinet.

Not much done yet apart from extracting the tuner/amp chassis from the cabinet and giving it a clean up (hoover and paintbrush), and having a nose around for any obvious problems. It doesn't look as though it's been meddled with in the past and the absence of a mains plug is encouraging as I don't think it's been used for some time.

Reading through the forum, I know I should change the output grid caps (two on this model, I believe - one for each ECL86) which I've circled in one of the attached pictures. There seems to be differing opinion on whether all wax capacitors should be changed... I'm sitting on the fence at the moment, and willing to listen to those with experience. Are there any other common problem caps on this model?

Although the chassis looks to be in original condition, I noticed two yellow wires to the left of one of the ECL86s looks to have been snipped. I have had a look online for pictures to confirm whether this is the case or not, but with no luck. I can't locate this on the schematic.

Finally, the mains transformer sits over a particularly large smoothing can. Given this can is, perhaps, older than I am, should I replace this as a matter of course? I imagine that could make quite a mess of things if it did go pop.

This won't be going anywhere near the mains until the crucial jobs have been done - including fitting a new 3-core mains cable - and I'll be building a lamp limiter too.
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