exxos's Atari, Amiga & retro forum

Hi everyone :)

I have photographed the internals of my 520ste now appears to be a 4160 with the 4mb upgrade from exxos store and a shiny new sticker of ebay haha. Other than a slight bit of dust inside its in very good condition.
The STE works well minus the floppy which spins, think it needs the caps replacing and service, there are some slight pale lines vertically on the display more noticeable on a dark screen and slight ghosting with graphics on a music and dancer demo software supplied with the sd4st hard drive. concerned about the PSU, I know they can get hot and potentially blow causing fatal damage! it has a smell, at 1st I was going to recap it, but i'm now considering purchasing one of these fine toroidal based psu's if it will keep the heat down improving the life of the motherboard plus any expansions I fit. I wish to add the Dual TOS and 32Mhz booster, all switchable including, I will be keeping the internal floppy as Im not keen on swapping it for a gotek, I have the external SD4ST HD, but shall be adding an external gotek boot priority switchable and possibly in a floppy enclosure at a later date. The floppy drive is a sony MPF 110-03 i've got the photos with part numbers and I will insert them inline below

I want to do the mandatory fixes where required on my machine, it is my understanding after reading in the forum that motherboards and psu's vary, perhaps someone will advise my psu has years on it and suggest the recap option, will the torroidal be vastly cooler? Will the torroidal have a cleaner smoother signal voltage path than the original? Everything ive read suggest so.

Also is it recommended the mainboard caps be replaced also?

Im hoping the cpu booster kit complete and tos switcher all available on the exxos store wilo be compatible with my motherboard? Photos here thanks


Big thanks, Jamie.

Jamie Zen wrote: 25 Jul 2023 18:58 I want to do the mandatory fixes where required on my machine, it is my understanding after reading in the forum that motherboards and psu's vary, perhaps someone will advise my psu has years on it and suggest the recap option, will the torroidal be vastly cooler? Will the torroidal have a cleaner smoother signal voltage path than the original? Everything ive read suggest so.

The toroidal is a much cooler beast than the original. IMO it's an excellent power supply. One might even argue it's overkill for machines that have put up with PSUs with failing caps for years, but if it's a straight choice between recap (essential if you keep the old one) or the toroidal? Well the toroidal for me all day long.

Also is it recommended the mainboard caps be replaced also?

I've not done any of my main boards capacitors, to be honest with you, but I probably would if I had the time. It's down to how comfortable you are doing the job. The motherboards are very easy to damage (much more so than the PSU boards where the balance of risk/reward is so much more in the reward camp). The big bulk capacitor is probably the main one to target and, if you get the new PSU, the capacitors in the reset circuit may need attention too.

Im hoping the cpu booster kit complete and tos switcher all available on the exxos store wilo be compatible with my motherboard?

I see no reason they shouldn't be. I've a TOS switcher board myself and it works well.

BW

I'd suggest that whilst the mandatory fixes are well worth doing, unless you have a specific issue I'd hold off doing too much.

It's all about managing risk, as @Badwolf mentioned. It is very easy to damage these boards if you're not familiar with them, and I have even experienced mechanical damage simply by handling boards.

It can be very difficult to find and fix hidden damage such as cracked vias or tracks that aren't noticeably damaged, plus there is a risk of pulling tracks when desoldering, which is something you really want to avoid.

If you do feel confident to do these fixes, I'd suggest you do one item at a time and confirm all is good afterwards. Troubleshooting multiple repairs is not fun.

In the case of the booster and TOS switcher and booster, you have both socketed ROMs and CPU, so I think you should be fine.

I'd just advise caution when routing the 32Mhz pick up wire as you can have issues with interference if you don't follow the suggested route.

The 32mhz booster has pull-ups already installed which negate the requirements of having to change them on the motherboard:

This one has SMT bus pullups (no need to solder them anymore! yay!) , so no need to change them on the motherboard either. They have always been on the V1 series, but in SIP format. Now I can get stuff assembled (at least in part) I went with SMT resistors packs.

source

And if you don't want to go 'full hog' on re-capping, just do the three most important caps:

1: The 4700uf centre capacitor
2 & 3: The reset capacitors, replace C100 with 47uf and C102 with 22uf source

Thanks very much everyone you have all been very helpful! I'm going to purchase the Toroid PSU and other parts. Just a thought if anyone happens to know if the cpu boost speed toggle switch gets knocked during operation can it cause any damage? Or is the booster designed to be switched during operation? Can it be software switched?

Thanks, Jamie. 8-)

Jamie Zen wrote: 26 Jul 2023 17:44 Thanks very much everyone you have all been very helpful! I'm Going to purchase the Toroid PSU and other parts. Just a thought if anyone happens to know if the cpu boost speed toggle switch gets knocked during operation can it cause any damage? Or is the booster designed to be switched during operation? Can it be software switched?

Thanks, Jamie. 8-)

It can't be software switched, but it can be changed during normal operation with the switch. It can go from 8 > 32mhz while the machine is on, and vice versa.

Steve wrote: 26 Jul 2023 10:57 The 32mhz booster has pull-ups already installed which negate the requirements of having to change them on the motherboard:

This one has SMT bus pullups (no need to solder them anymore! yay!) , so no need to change them on the motherboard either. They have always been on the V1 series, but in SIP format. Now I can get stuff assembled (at least in part) I went with SMT resistors packs.

source

And if you don't want to go 'full hog' on re-capping, just do the three most important caps:

1: The 4700uf centre capacitor
2 & 3: The reset capacitors, replace C100 with 47uf and C102 with 22uf source

Don't forget the 35v 470uf one of the left of the picture. The problem with these 2 bigs on the mainboard is that they dry :/

@Dlfrsilver Oh yeah that one in particular because it's reversed polarity (incorrect) by default, always needs replacing and swapping polarity.

Jamie Zen wrote: 26 Jul 2023 17:44 Just a thought if anyone happens to know if the cpu boost speed toggle switch gets knocked during operation can it cause any damage? Or is the booster designed to be switched during operation?

Thanks, Jamie. 8-)

In my experience (I have 2 STE's with 32Mhz boosters), you won't do any harm by switching the frequency when the machine is on, but there is a strong possibility that whatever you're running at the time will crash.

At least that is my experience of things.

There is no software switch as Steve said.

Hi Thanks again everyone you have all been very helpful, I am really glad I found the Exxos Store, and the Forum so big thumbs up and thanks @Exxos for that.

I have decided to replace the PSU with the torroidal one and install the Dual Tos board for now until funds allow then I shall purchase the CPU Booster :-) 8-) I shall be looking at the other items discussed, larger caps on the board, also I must fix the floppy drive :-) quite certain it's the caps on that.

Best wishes everyone and thanks :-) Jamie