The long story short is that when I was young, early twenties, I had one of these machines. I was facing a very large decision in my life, one which would ultimately rip me from my family
(took years to heal some of the wounds and still healing) .... and this unit kept me company on some very late night walks around Sheffield.
Anyway... I was burgled. The sod took all my hifi equipment. I managed to get most of it back through some quick thinking
(covered in fingerprint dust) but the Aiwa was fenced before the police caught up to him. He denied taking it. Got 100 hours community service and the landlady kicked me out, "for fear of reprisals."
You know how you get those ghosts in your life that are with you for years and you just have to lay them to rest? Well, this is one of those things for me. A 25 year-ish ghost that I'm hoping to put to bed.
So... I've been trying to find one of these for some time. They are quite rare and people tend to keep hold of them once they've got them. However, everything needs recapping and I'm practising on a HS P505 walkman. Have currently decapped it, isolated a microswitch fault, cleaned off the worst of the capacitor leakage and am about to do a 1 part distilled water to 3 part bicarb paste, to neutralise whatever is left. Then another bath and long dry, before installing the new caps, and run it up on the bench.
If I can get the P505 working fine, and my soldering technique sorted (I'm currently practising on SMD training kits) then I'll start work on the 303 units. I'm also expecting microswitch failures, and am wondering how I'm going to get parts.
All the caps are here, and I do have an Aiwa 2V PSU, but no battery compartment. I'm sort-of in talks with someone who has one, and a silver PX303... but that's going slowly at the moment.
Someone has gifted me two on the proviso that if I get them both working, I send one back to him... and it looks like it might be an IC failure, from what little I've seen so far. That's one reason why I can't put the diodes inside the unit.
So... power is a thing.
I have also got some of these coming -
https://www.ebay.co.uk/itm/AMS1117-1-2-5V-DC-Step-Down-Voltage-Regulator-Adapter-Convertor-Supply-Module-B2/322980775873 - in the hope that it will run on 1.8v, and if it does then I can rig an external battery that will run off a USB battery. I'd have to make a custom case, though. Not sure how I'd handle that yet. Basically, I've got a lot of bench testing to do... which will be done through the month, as it will take many weeks for all this to come from China.
I did receive news yesterday that someone has made PB-3 cells with a LiPo inside, but given what's been said in this thread, I'd rather be in control of my own build, rather than someone elses.