exxos's Atari, Amiga & retro forum

stephen_usher wrote: 13 Apr 2025 10:24 Don't get me wrong... there's no real way to visit a lot of these places without being on a ship, it was worth it for that.

Just don't sign up for the "excursions" as most of them were local and could have been just as well just walking, saving a few hundred pounds each!!! (There were two notable exceptions with reasonable distant coach travel, but these turned out to be the cheaper ones!!!)

It seemed that most of the people on the ship had come in largish groups from Australia and the USA and spent a lot of the time in the forward bar just drinking together from the time the bar opened at 1pm until late evening, using their "food and drink" package to the full.

Ahh OK. Good to know about the excursions, we did a trip to Tunisia and it was a bit like that, with some excursions being heavily geared around getting you into rug stores!! We went to Sandals in Antigua for our honeymoon and the Americans were very much like that in the bars and restaurants. I think it's a given wherever you go.

Spare case and PSU brought down from the loft...

Tested the output caps on the PSU, three dodgy ones, now replaced. Tested and the voltages are good... So a bit of an iffy lash-up to test things.


Once I have obtained a PSU bracket this should go back together easily and be a good 4MB STFM.

Oh, and a fitted the replacement opto-isolator on the MIDI port as those chips arrived whilst I was away and the keyboard still works. I can't test the MIDI interface any further but I assume the AliExpress PC900 chips are OK.

Back to working on preparations for RetroFest2025 again this afternoon, rationalising the prototype track design for the layout.

A bit of a scare when one of the locos stopped and then proceeded to make smoke. I took it to the bench and serviced the motor, cleaning the commutator, removing a lot of old carbon, cleaning out the old oil and relubricating. All working now.

The planed wood for the baseboard framing arrives tomorrow and the plywood next week, hopefully, so I can then get on with actually building it. Only about 6 weeks to go, so it's going to be tight getting this ready!

stephen_usher wrote: 16 Apr 2025 20:21 A bit of a scare when one of the locos stopped and then proceeded to make smoke. I took it to the bench and serviced the motor, cleaning the commutator, removing a lot of old carbon, cleaning out the old oil and relubricating. All working now.

😱

Anyway, looks really good now !

What's on the bench today?

It's my 1977 vintage cassette recorder, which I used to use with my ZX81 and ZX Spectrum until about 1984 when it started warbling a bit and wouldn't load tapes. (I switched over to using my Uncle's identical recorder, which seems to have been thrown away by my Dad in one of his "clear outs" in the 1990s.)

I've managed to fix the warbling with relubrication and straightening the flywheel on the capstan drive pin. Goodness knows how that got bent. However, the audio is pretty distorted and recording doesn't work at all. So, it's time for a recap.

Those 48 year old Rubycon caps are pretty arthritic.

I've stock of all of the caps except for the three 33uF ones and the 3.3uF. Taking one of those 33uF caps out and testing it showed that it was over 60uF and with greater than 3% leakage. Not good at all. Getting them out is a pain as they've used horrid beige glue all over the board. Thankfully it's not gone conductive.

Anyway, I now have to wait for the delivery from Farnell. RS had all the caps I needed "on back order" with an estimated delivery sometime in 2026!

P.S. On the railway front. I discovered yesterday that I'd made a scaling error on the plywood sheets... as in I'd typed into the ordering web page the dimensions in cm but the page was using mm! So, I've had to put another order in with the correct dimensions, but this will delay the build for another week, giving only 4 weeks to complete it all.

Couldn't wait for the 33 and 3.3 uF caps to arrive so put some 47 and 4.7 uF ones in as placeholders.

Sounds a heck of a lot better but the speccy won't load tapes from it and on the 'scope the output has too much high frequency filtering. Still, I've not broken it, which is the important thing.

Ahh, I had something similar back in the day :) Good to see it getting some love :)

The new 33uF and 3.3uF caps arrived today. Unfortunately I could only get bipolar caps rather than polarised ones, but that shouldn't matter.

Fitted them and the tape playback sounds OK but the Spectrum doesn't even recognise the header. Recording is another matter, totally screwy and distorted.

All I can think of is that the Orion/Toshiba amplifier chip has gone bad as all the electrolytics have been changed with the correct values.

Oh well.

And... the miniature baseboards have arrived. :lol:

stephen_usher wrote: 23 Apr 2025 12:33 The new 33uF and 3.3uF caps arrived today. Unfortunately I could only get bipolar caps rather than polarised ones, but that shouldn't matter.

Fitted them and the tape playback sounds OK but the Spectrum doesn't even recognise the header. Recording is another matter, totally screwy and distorted.

All I can think of is that the Orion/Toshiba amplifier chip has gone bad as all the electrolytics have been changed with the correct values.

Oh well.

And... the miniature baseboards have arrived. :lol:

I can't recall, did you replace the drive belt(s) and clean all the drive pulleys etc?

rubber_jonnie wrote: 23 Apr 2025 14:04 I can't recall, did you replace the drive belt(s) and clean all the drive pulleys etc?

Yes, I refurbished all of that first.