Today I picked up 3 x Atari ST

[groppo91]

Probably an impulse buy especially as they have been long time stored in a shed but I noticed one had a badge saying 4160ST. I know these badges are aftermarket but intrigued me into the purchase. I have since found out from the bases of the machine one looks like 520STE, another is a 1040STFM and the final one I think says 520st. 

 

I paid £90 which is £30 each i guess so not too bad. I do not want to power on until they have been cleaned and checked.

 

What would people recommend I do before switching on?

 

Would it be best to isolate the PSU amd test the output, if so how do I go about this my knowledge starts amd ends with modern atx psu?

 

I have purchased some 99.9% alcohol to give the boards a good clean.

 

Anything useful links to guides etc for refurb/bringing back to life long term stored atari st?

[bfollowell]

If the case badge

55 minutes ago, groppo91 said:

Probably an impulse buy especially as they have been long time stored in a shed but I noticed one had a badge saying 4160ST. I know these badges are aftermarket but intrigued me into the purchase. I have since found out from the bases of the machine one looks like 520STE, another is a 1040STFM and the final one I think says 520st. 

 

I paid £90 which is £30 each i guess so not too bad. I do not want to power on until they have been cleaned and checked.

 

What would people recommend I do before switching on?

 

Would it be best to isolate the PSU amd test the output, if so how do I go about this my knowledge starts amd ends with modern atx psu?

 

I have purchased some 99.9% alcohol to give the boards a good clean.

 

Anything useful links to guides etc for refurb/bringing back to life long term stored atari st?

says 4160ST, then yes, it isn't official. If it says 4160STE, it very well could be the real thing. I have an original, official 4160STE case badge on mine. Atari originally sent these to developers but later made them available to consumers that had upgraded their machines to 4MB.

 

Good haul!

 

[TGB1718]

1 hour ago, groppo91 said:

Would it be best to isolate the PSU amd test the output, if so how do I go about this my knowledge starts amd ends with modern atx psu?

If they are all internal power supplies, once opened up, there's a plug you can disconnect from the motherboard, with

that pulled, there's no power to the ST, be careful though, lot's of exposed components in the PSU's that could potentially hurt.

 

Can't remember, but you may have to remove the RF shield to do this.

[groppo91]

Looks like its the genuine badge given out to developers. Guess this is worth something alone? I will probably keep it for my final refurb build. 

 

Edited October 27, 2023 by groppo91

[TZJB]

9 minutes ago, TGB1718 said:

If they are all internal power supplies, once opened up, there's a plug you can disconnect from the motherboard, with

that pulled, there's no power to the ST, be careful though, lot's of exposed components in the PSU's that could potentially hurt.

 

Can't remember, but you may have to remove the RF shield to do this.

 

I don't believe that the PSU RF shield would need to be removed to access the PSU output socket, but will probably need to come off anyway in order to inspect the electrolytic capacitors for leaking and bulging.

 

From memory there are sometimes hidden bolts holding the PSU RF shield at the back near the power entry, the rest are visible.

 

Definitely test the PSU outside of the machine with a load of some description. Although the 5V supply is the most important, I tend to test using an old 3.5" hard drive or similar as both 12V & 5V are then loaded.

 

As @TGB1718 said, most 120/240V parts are insulated, but care is still needed when the power is applied especially around the bridge rectifier which is normally exposed.

[groppo91]

Thankyou for the advice on the psu. I saw a video on youtube of someone testing the psu with some load resistor are these special and if so does anyone recommend which ones to purchase? They also desoldered the caps and installed new ones followed by the bridge rectifier which they swapped for some weird thin black component that had 4 or 5 legs. Is this still the recommended refurb in 2023? My next question is caps i seem to remember my college days whereby we had drain the caps before working on them am I right in saying this is done by bridging the pins with a screwdriver or resistor of some sort? 

 

Lastly the bridge rectifier if as dangerous as people make out how do I safely work on this? 

[+DarkLord]

Good deal on all 3 machines - congratulations! 

 

[Zogging Hell]

1 hour ago, groppo91 said:

Thankyou for the advice on the psu. I saw a video on youtube of someone testing the psu with some load resistor are these special and if so does anyone recommend which ones to purchase? They also desoldered the caps and installed new ones followed by the bridge rectifier which they swapped for some weird thin black component that had 4 or 5 legs. Is this still the recommended refurb in 2023? My next question is caps i seem to remember my college days whereby we had drain the caps before working on them am I right in saying this is done by bridging the pins with a screwdriver or resistor of some sort? 

 

Lastly the bridge rectifier if as dangerous as people make out how do I safely work on this? 

You can get PSU recap kits and a load resistor from https://www.exxosforum.co.uk/atari/store2/ . I think as long as you are not working with the rectifier or caps when power is on (i.e. you just want to keep your distance when testing and get things set up for test with power off) and take some insulation precautions then you should be relatively safe from a zap. I've never had one from the ST PSU with the power off, if the computer has been off for a while, and I've done some fairly stupid things. Particularly if you don't power on the PSU at all before the test as they have been sitting in a shed for years and have probably discharged. Depending on the size of the cap in can be ok to bridge the pins, but I think the 'best practise' method is to drain them to ground (not motherboard ground) before doing that. This is quite a good resource https://www.repairfaq.org/sam/captest.htm#ctbcs if you are worried, although the caps they are talking about are very high voltage CRT ones and carry a bit more kick than the ST ones.

 

Personally if they have been in a shed I would strip them down completely and check beneath the metal shielding. If water or damp has got in there then you do not want to be powering on at all (I would probably make sure they are somewhere dry and warm for a good period before power on anyway). If you get the shielding off you can inspect for any signs of corrosion or damage, and also make sure nothing has..err.. nested in them.

 

Congrats on that deal though, best one I've seen in ages... in fact that is an early noughties cost deal, although not quite as good as my Falcon for £15 and TT for £25 one

Edited October 27, 2023 by Zogging Hell

[groppo91]

Thankyou, he had them listed at £500 offers and they were relatively local I asked weeks ago if they were available still and said yes then I left it a few weeks amd asked if he would take £80 he wanted £100 but because they were untested amd rough I thought £80 was fair. Eventually I went in at £90 and was a done deal. The guy lived in a very awkward place though but I look forward to working on them. I may set myself a project to document it all on here when I finally get the time. Maybe in the new year. 

[groppo91]

With the 4160 STE badge it seems to be ribbed on the metal like the stock badges. I guess this is original as the aftermarket ones on ebay all appear smooth. Is there much information on these badges and if they are valuable at all. 

[bfollowell]

You can still but them NOS from Best Electronics, so I wouldn't think especially valuable at all. I bought mine a couple of years ago for like $8-$10.

 

And like I said earlier, these were originally installed on developer's machines that went out. Later, Atari made them available to consumers that had their machines factory upgraded to 4MB. If you took your machine in to an official service center and had it upgraded, it would come back with this new case badge installed. Many people didn't upgrade their machines at all. Still, many more just upgraded themselves, like me. Brad shows he still has these in stock for $10 each, part number CB102025. Like most everything that Brad sells, these are NOS parts, not remake parts.

 

[groppo91]

2 minutes ago, bfollowell said:

You can still but them NOS from Best Electronics, so I wouldn't think especially valuable at all. I bought mine a couple of years ago for like $8-$10.

 

And like I said earlier, these were originally installed on developer's machines that went out. Later, Atari made them available to consumers that had their machines factory upgraded to 4MB. If you took your machine in to an official service center and had it upgraded, it would come back with this new case badge installed. Many people didn't upgrade their machines at all. Still, many more just upgraded themselves, like me. Brad shows he still has these in stock for $10 each, part number CB102025. Like most everything that Brad sells, these are NOS parts, not remake parts.

 

Ah thats good to know. All the ones I could see look nice but not original quality like the one I just got. Just thought it was special once I saw it but guess not if Brad has a load of them.

[bfollowell]

15 minutes ago, groppo91 said:

Ah thats good to know. All the ones I could see look nice but not original quality like the one I just got. Just thought it was special once I saw it but guess not if Brad has a load of them.

Yes, that's just those though. I don't believe he has any of the others left.

 

[Jfcatari]

Console 5 also has CAP kits

 

https://console5.com/store/catalogsearch/result/?q=atari+st

 

 

[CommodoreDecker]

23 hours ago, groppo91 said:

Probably an impulse buy especially as they have been long time stored in a shed but I noticed one had a badge saying 4160ST. I know these badges are aftermarket but intrigued me into the purchase. I have since found out from the bases of the machine one looks like 520STE, another is a 1040STFM and the final one I think says 520st. 

 

I paid £90 which is £30 each i guess so not too bad. I do not want to power on until they have been cleaned and checked.

 

What would people recommend I do before switching on?

 

Would it be best to isolate the PSU amd test the output, if so how do I go about this my knowledge starts amd ends with modern atx psu?

 

I have purchased some 99.9% alcohol to give the boards a good clean.

 

Anything useful links to guides etc for refurb/bringing back to life long term stored atari st?

 

Apologies if any of the following has been mentioned:

 

I'd get a voltmeter and check the power supplies to make sure the 12v and 5v outputs are within spec (~ +/-1v, ideally.)  Chances are, they'll work but will need to be replaced. The brand Mean Well has a couple models like the RDP-60A and RD-50A-VP.  The RD-50A is a little easier to wire up, but you'll have to remove its top shield and be careful as it's a tight fit.  The 60A unit is much more compact, but you need to find a TE 2154828-2 three-wire connector to hook up to the AC port.  With both these models, de-solder or clip off the power supply coupler's leads and, if you have to splice, use the same gauge wire - a smaller might cause problems...

 

For the non-STF/FM models, which I'm beginning to have respect for since they don't integrate the power supply and are easier to deal with, check this out:  https://www.ebay.com/itm/115823250318?hash=item1af79a8b8e:g:OkUAAOSwkjFkewfF&amdata=enc%3AAQAIAAAA8NalcL2j%2BaKkbnRhriUe%2FVKud0w4vVlxjydaudkRA67P5iq14lGykR6iaQVzBAdUQxT8TyaTikJZveV5PnTv4Et0Ma1oCUpBl2wiW8igLsFFhqHflgrPfH05BwSD3Qi6tqAXCXC9uvzzZc2mkHt3TuQJslETbkKySkBevUfoS%2BAjcP%2BFjVN5bbJ0p9ZHUVKM%2BEFVN4EdraEFhZTWYcjuRthG7UhHBKr5o9OSjDBGL66CZl4d11%2FXfxAQ7VPZHRGFpsrieX6rt1JHJo%2FYSgk4BFkx8%2BMWvtxfQ4JIgQoMhPOarecS0ofLYm1PMTBBC9uYxg%3D%3D|tkp%3ABk9SR_D1veHuYg

 

I bought one and they're slick, replacing both the ST PSU and the 314/354 disk drive's as well.  Looks like you're in the UK, but I think that company makes 240v equivalents. 

 

 

I'd also look up replacing the capacitors. Not just in the power supply unit for the STFM, but any on the mainboard for all of the computers as well.  Wavy lines and crashes/reboots are often a sign of a failing capacitor... The shelf life is typically a decade before these start to go waver, and these are 30+ years old and it looks like they were stored in an area not climate-controlled, so they probably took a beating during dry winters and humid summers.  (That said, I've seen plenty of Atari 800s and Nintendo NES units operate fine, with no wavy lines or instability, so YMMV. Still, when in doubt, swap 'em out.  The cleaner electrical flow as a result will extend the lifespan of the other components, and the microchips are the most difficult to have to replace.) 

 

 

 

 

[CommodoreDecker]

12 hours ago, Jfcatari said:

Console 5 also has CAP kits

 

https://console5.com/store/catalogsearch/result/?q=atari+st

 

 

 

Exxos is a UK site. Console5 has similar prices and is US-based (so if you're in the US, shipping will be lower than Exxos, but you're in the UK so it'll cost more...)  Part of me wishes I'd seen Console5 before as I'm in the US, but the more I'd read Exxos's site, it's worth it. They also went to great lengths to make a custom capacitor replacement for the main 4700uv/16v capacitor:

 

https://exxosforum.co.uk/atari/last/caps/index.htm

 

Their description and reasoning won me over.

 

Can't go wrong with either store, though!

 

Edited October 28, 2023 by CommodoreDecker

[Bikerbob]

I have built machines (H5 Phoenix) and repaired many others, expansion boards etc with just purchase from Digikey.  Learn the values of your components, order them (I think your in UK though)  Shipping from Exxos is crazy to North America. But he is a great resource for information and parts (in the UK) 

 

James

[TZJB]

On 10/27/2023 at 4:59 PM, groppo91 said:

Thankyou for the advice on the psu. I saw a video on youtube of someone testing the psu with some load resistor are these special and if so does anyone recommend which ones to purchase? They also desoldered the caps and installed new ones followed by the bridge rectifier which they swapped for some weird thin black component that had 4 or 5 legs. Is this still the recommended refurb in 2023? My next question is caps i seem to remember my college days whereby we had drain the caps before working on them am I right in saying this is done by bridging the pins with a screwdriver or resistor of some sort? 

 

Lastly the bridge rectifier if as dangerous as people make out how do I safely work on this? 

 

The load test resistors are low value high wattage wire wound resistors. Exxos discusses these and their values on his website and can supply a kit. 2.2 Ohms for 5V and 10-22 Ohms for 12V.

 

As for the capacitors, even if you have powered the PSU recently there is normally no need to manually drain them of charge as they will self-discharge rapidly anyway. However, check with a voltmeter set to the expected range to be safe.

 

Regarding the thin black bridge rectifier mentioned, again this is probably from an Exxos kit where he provides higher rated low tension Panasonic FR spec capacitors than stock, together with a higher rated 400/600V 6-10 Amp bridge rectifier which is consequently rectangular and bigger than the cylindrical stock 1.5 Amp part, with the caveat of requiring bigger holes in the PCB to mount it.

 

I chose to successfully use a cylindrical 600V 2 Amp bridge rectifier, which looks similar to the stock part and seems to survive the higher switch-on surge, plus the holes in the PCB don't need to be drilled. I also insulated the leads for more safety.

 

To answer your question regarding recommended refurb, this is down to personal choice. You may either repair the PSU with new electrolytic capacitors, or replace it completely with probably a more efficient device. The choice may be down to cost or something else. For me it was something to refurbish, which I like doing, at minimal cost.

 

The bridge rectifier is only lethal if you touch the exposed leads with your fingers when the 200/400V high tension capacitor/s are charged, i.e when the PSU is powered from the mains supply or still holding a charge soon after disconnection. As I said, check if charged using a voltmeter set to the relevant DC range. They should be seen to discharge quickly due to the PSU's own inbuilt inefficiencies.

 

The capacitors can be discharged manually with, say, an insulated meter lead directly across the capacitor terminals, which will cause a spark if charged. Or possibly more safely through a fully insulated 10-22R wire wound resistor.

 

So long as you measure no voltage across any capacitor, you can expect to work safely on the PSU PCB. Always double check for your own safety.