GRID PSU, definitely 'Not Working' ! - UK Vintage Radio Repair and Restoration Discussion Forum

Buzby123 · 25th Mar 2021, 12:05 pm

While waiting for my parts to arrive for Micky, I thought I'd have a look at another project which has been on the back burner for years.

It's a GridCase 1530 laptop, I got it off eBay for pennies. The seller described it as 'Not Working'.

The PSU is a module that can either fit in the laptop, or be used to power a battery charger. The PSU was giving zero volts out, so I opened it up to check for fuses etc.

Imagine my dismay when I found that half the gubbins are missing !.

There are no power devices in the Q1 Q2 positions, and there are two big capacitors missing. The 'Not Working' description was spot on !.

I don't think there is much chance of fixing this, so my plan is to remove the internals completely and hide a modern SMPS inside.

What does the team think ?

Cheers,

Buzby

SiriusHardware · 25th Mar 2021, 1:04 pm

One thing you might want to consider is applying 16.25V to whatever that normally connects to to see if the computer itself works. If it does not, it may not be worth any amount of effort to fix the PSU.

As it appears to be single-voltage out I would say you have good prospects for fitting a smaller more modern (but similarly rated) PSU inside that one - just need to make sure it has some leeway in the adjustment of the output voltage - one described as 15V-out will most likely be be able to adjust up and down a couple of volts.

Buzby123 · 25th Mar 2021, 1:39 pm

I removed all the gubbins, then wired a 16.2v supply to the two pads at the back of the PSU.

The PSU pads don't seem to make proper contact inside the laptop, I needed to push the PSU tightly to get the following picture.

Worth a bit more exploring, methinks !.

SiriusHardware · 25th Mar 2021, 2:16 pm

Most likely whatever it is that makes contact with those flat pads on the PSU are spring-loaded to a degree, maybe they've lost a bit of their 'boing'.

A good start anyway - what are the internal dimensions of the original PSU cage?

philip_s · 25th Mar 2021, 3:32 pm

Quote:

Originally Posted by Buzby123

There are no power devices in the Q1 Q2 positions, and there are two big capacitors missing. The 'Not Working' description was spot on !.

Are these the only missing components? Last year I posted about replacing the capacitors in an identical PSU (the Rifa-style ones near the mains socket). The pictures aren't clear enough to make out the details you need, but would be happy to open it back up and note the values for your missing components if you're wanting to repair the board.

Re: the PSU not making good contact, the contacts do lose a bit of springyness over the years and can be bent back outwards. Either hook them from outside with a loop of wire, or you can take the rear top cover off to access the battery compartment.

Buzby123 · 25th Mar 2021, 3:38 pm

Here are the dimensions of the PSU cage, and a picture of the boot sequence. I've always wanted a plasma display laptop !

I'm now Googling for instruction on how to access the HDD, and CMOS battery.

ortek_service · 25th Mar 2021, 3:57 pm

I do recall using these at work many years ago, with their slot-in battery packs of the same size (Something a few others like DataGeneral did). And I think there was a lead from that 3pin Mini-DIN socket, to Laptop, in order to charge a battery fitted into the Laptop's slot(s) - Can't remember if this had two.
The modules used to go in with a solid click from retention mechansim that should endure a good contact with internal spring-contacts (that may have got damaged slightly.
They are just an Amber backlit LCD (some others were green), rather than just the usual black & white ones at the time -So not actually colour Plasma.
I think I've got a Toshiba 'Portable' (mains-powered only) 386 one that's got an Amber screen, before they moved onto Colour TFT's 486 ones.

It may have been possible to resurrect the original PSU if it is just 4 parts missing, given a photo of the insides of a complete one. Although there could be anther fault, that damaged original transistors. But not sure why the mains reservoir ones were missing (probably round 2200uF at 200V each if in series), unless someone had used it to raid for parts (So better described as incomplete rather than faulty, if had been got at.

No doubt the CMOS RAM battery will need replacing. And someone may have removed the original HDD from it.

SiriusHardware · 25th Mar 2021, 4:06 pm

If it even has an HDD? Could probably at least boot it from a 'Windows recovery floppy' created by Win '98, - essentially a DOS boot disc.

ortek_service · 25th Mar 2021, 5:07 pm

These do seem to have an HDD originally on this (1988) model.
Grid(UK) are still going, with it on their history. And there's info that Grid computers went up in the Space Shuttle! https://americanhistory.si.edu/colle...ct/nmah_211365

There's isnt a lot of detailed info on the HDD on the 1530, but some other spec's and it seems it is often referenced as having an Orange or Red Plasma VGA display - But looked to me just like the Amber (LCD?) ones I'd used on Toshiba's etc.
And conflicting info if this one had a Dallas RTC module soldered in, or separate battery: http://www.vcfed.org/forum/showthrea...ay-Portable-PC

There is a whole collection of Grid ones here:
http://staff.salisbury.edu/~rafantin...0_and_1530.htm
- I'm sure I have the odd Grid accessory, as the external 5.25" drive looks very familiar. But not sure about battery / PSU.

Yes, it should boot from any DOS - Even download of FreeDOS etc. - Boot disk. Just need to have a PC that's still got a FDD and maybe use rawwrite etc. util to create a disk with the required sytem files in the right place if you haven't already got an older DOS / Win-9x based system to do a format /s on.

Buzby123 · 25th Mar 2021, 5:27 pm

Quote:

Originally Posted by philip_s

... Last year I posted about replacing the capacitors in an identical PSU

Hi Phil, welcome to the forum.

The power of the Internet !. How convenient that you have worked on one of these so recently.

If you could kindly tell me what Q1 and Q2 were, the two big caps, and another cap, C7.

There also appears to be a coil missing, L5. Not sure what this is, but if it's just choke or similar it should be easy enough to find or wind a replacement.

One of the X2 caps doesn't look healthy, so I'll replace them as well.

I'd really like to get this going, without gutting it and stuffing a modern part in.

I think the next challenge is the CMOS and battery, so I'm going to follow your instructions !.

Cheers,

Buzby

Electronpusher0 · 25th Mar 2021, 8:10 pm

Are you sure that the components have been removed? Check the underside for signs of being desoldered, it may be that the components were never fitted.
Its not unusual for manufacturers to use one pcb for several supplies, fitting components as required for that application.
If that is the case, fitting the components could make matters worse.

Peter

Buzby123 · 25th Mar 2021, 8:58 pm

Quote:

Originally Posted by Electronpusher0

Are you sure that the components have been removed ?...

Good idea, but I'm fairly certain a switchmode PSU would need some chunky transistors, and some smoothing caps. Also, on the back of the board, one track for a capacitor is missing, as if it was lifted during de-soldering.

If I can't discover what the missing parts are it's no too much of an issue, I'll stuff a modern PSU in the existing case.

Quote:

Originally Posted by ortek_service

They are just an Amber backlit LCD

I think you might be right. A close look at the screen shows the lit pixels are clean squares, whereas I would expect plasma to have a bit of 'fuzziness'.

Cheers,

Buzby

nigelr2000 · 25th Mar 2021, 9:02 pm

One track connects to the bottom and one to the top with the 2 connected ones adding up to 4 connections it's just the little circles missing not a track.

Buzby123 · 26th Mar 2021, 10:06 am

The transformer in this PSU, it's his birthday today !.

ortek_service · 26th Mar 2021, 4:10 pm

At least they left that in there!

I did wonder if the electrolytic capacitors had been removed, to get better access to the transistors, as it seems it's quite compact in there. Although from some photos it looked like these capacitors may have been low-height ones so may have not been such an obstruction / finding correct size could be a bit more involved.
And they hadn't been removed too well, loosing a top & a bottom pads (plus possibly the hole's through-plating), when it's normally possibly to heat both pins at once and pull out these, without any damage.

Buzby123 · 26th Mar 2021, 4:50 pm

The 1530 has returned to the back burner !.

The DS1287 was dead, that's what the Code 2 error means. So I did the 'drill hole and add new battery' hack. I presume this worked, as now there is no error code at boot up.

Unfortuately the fault now reported is HDD failure, and it also it won't boot from a floppy either.

I've got bigger fish to fry, so I'm leaving the faulty PSU, and faulty computer, for another day.

Cheers,

Buzby

ortek_service · 26th Mar 2021, 5:15 pm

(If you haven't already done it):
Next time you work on it, try going into BIOS set-up and resetting to factory default / check HDD & FDD settings, as these will probably have been lost by low DS1287 battery which will also back up its 'CMOS' RAM.

Buzby123 · 26th Mar 2021, 5:21 pm

I don't know how to get into BIOS setup.

If the problem is just BIOS settings I will have another go tomorrow !.

Cheers,

Buzby

SiriusHardware · 26th Mar 2021, 6:06 pm

On PCs of that era with typical 'AWARD' or 'Phoenix' BIOS it was common to get into the BIOS by repeatedly hitting DEL during the boot process, although laptops / portables often deviated from that because they tended to have a reduced number of keys.

If you read carefully what the machine says on the screen during boot-up it will often tell you what you have to press to get into the BIOS.

SiriusHardware · 26th Mar 2021, 6:31 pm

I found this old mega-thread elsewhere...

http://www.brutman.com/RuGRiD/RuGRiD_part2.html

...When I was trying to find out for sure how to get into the BIOS.

It discusses several GRID models as it meanders but one of the surprising things which comes up - it may or may not apply to your model - is that the type of HDD fitted may be hard-coded into the BIOS as there is talk of editing the BIOS ROMs to make them work with other HDDs.

If so, this is very hardcore indeed.

25th Mar 2021, 12:05 pm	#1
Buzby123 Heptode Join Date: Oct 2011 Location: Culcheth, Cheshire, UK. Posts: 654	GRID PSU, definitely 'Not Working' ! While waiting for my parts to arrive for Micky, I thought I'd have a look at another project which has been on the back burner for years. It's a GridCase 1530 laptop, I got it off eBay for pennies. The seller described it as 'Not Working'. The PSU is a module that can either fit in the laptop, or be used to power a battery charger. The PSU was giving zero volts out, so I opened it up to check for fuses etc. Imagine my dismay when I found that half the gubbins are missing !. There are no power devices in the Q1 Q2 positions, and there are two big capacitors missing. The 'Not Working' description was spot on !. I don't think there is much chance of fixing this, so my plan is to remove the internals completely and hide a modern SMPS inside. What does the team think ? Cheers, Buzby Attached Thumbnails

25th Mar 2021, 1:04 pm	#2
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,560	Re: GRID PSU, definitely 'Not Working' ! One thing you might want to consider is applying 16.25V to whatever that normally connects to to see if the computer itself works. If it does not, it may not be worth any amount of effort to fix the PSU. As it appears to be single-voltage out I would say you have good prospects for fitting a smaller more modern (but similarly rated) PSU inside that one - just need to make sure it has some leeway in the adjustment of the output voltage - one described as 15V-out will most likely be be able to adjust up and down a couple of volts.

25th Mar 2021, 1:39 pm	#3
Buzby123 Heptode Join Date: Oct 2011 Location: Culcheth, Cheshire, UK. Posts: 654	Re: GRID PSU, definitely 'Not Working' ! I removed all the gubbins, then wired a 16.2v supply to the two pads at the back of the PSU. The PSU pads don't seem to make proper contact inside the laptop, I needed to push the PSU tightly to get the following picture. Worth a bit more exploring, methinks !. Attached Thumbnails

25th Mar 2021, 2:16 pm	#4
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,560	Re: GRID PSU, definitely 'Not Working' ! Most likely whatever it is that makes contact with those flat pads on the PSU are spring-loaded to a degree, maybe they've lost a bit of their 'boing'. A good start anyway - what are the internal dimensions of the original PSU cage?

25th Mar 2021, 3:38 pm	#6
Buzby123 Heptode Join Date: Oct 2011 Location: Culcheth, Cheshire, UK. Posts: 654	Re: GRID PSU, definitely 'Not Working' ! Here are the dimensions of the PSU cage, and a picture of the boot sequence. I've always wanted a plasma display laptop ! I'm now Googling for instruction on how to access the HDD, and CMOS battery. Attached Thumbnails

25th Mar 2021, 3:57 pm	#7
ortek_service Octode Join Date: May 2018 Location: Northampton, Northamptonshire, UK. Posts: 1,440	Re: GRID PSU, definitely 'Not Working' ! I do recall using these at work many years ago, with their slot-in battery packs of the same size (Something a few others like DataGeneral did). And I think there was a lead from that 3pin Mini-DIN socket, to Laptop, in order to charge a battery fitted into the Laptop's slot(s) - Can't remember if this had two. The modules used to go in with a solid click from retention mechansim that should endure a good contact with internal spring-contacts (that may have got damaged slightly. They are just an Amber backlit LCD (some others were green), rather than just the usual black & white ones at the time -So not actually colour Plasma. I think I've got a Toshiba 'Portable' (mains-powered only) 386 one that's got an Amber screen, before they moved onto Colour TFT's 486 ones. It may have been possible to resurrect the original PSU if it is just 4 parts missing, given a photo of the insides of a complete one. Although there could be anther fault, that damaged original transistors. But not sure why the mains reservoir ones were missing (probably round 2200uF at 200V each if in series), unless someone had used it to raid for parts (So better described as incomplete rather than faulty, if had been got at. No doubt the CMOS RAM battery will need replacing. And someone may have removed the original HDD from it. Last edited by ortek_service; 25th Mar 2021 at 4:03 pm.

25th Mar 2021, 4:06 pm	#8
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,560	Re: GRID PSU, definitely 'Not Working' ! If it even has an HDD? Could probably at least boot it from a 'Windows recovery floppy' created by Win '98, - essentially a DOS boot disc.

25th Mar 2021, 5:07 pm	#9
ortek_service Octode Join Date: May 2018 Location: Northampton, Northamptonshire, UK. Posts: 1,440	Re: GRID PSU, definitely 'Not Working' ! These do seem to have an HDD originally on this (1988) model. Grid(UK) are still going, with it on their history. And there's info that Grid computers went up in the Space Shuttle! https://americanhistory.si.edu/colle...ct/nmah_211365 There's isnt a lot of detailed info on the HDD on the 1530, but some other spec's and it seems it is often referenced as having an Orange or Red Plasma VGA display - But looked to me just like the Amber (LCD?) ones I'd used on Toshiba's etc. And conflicting info if this one had a Dallas RTC module soldered in, or separate battery: http://www.vcfed.org/forum/showthrea...ay-Portable-PC There is a whole collection of Grid ones here: http://staff.salisbury.edu/~rafantin...0_and_1530.htm - I'm sure I have the odd Grid accessory, as the external 5.25" drive looks very familiar. But not sure about battery / PSU. Yes, it should boot from any DOS - Even download of FreeDOS etc. - Boot disk. Just need to have a PC that's still got a FDD and maybe use rawwrite etc. util to create a disk with the required sytem files in the right place if you haven't already got an older DOS / Win-9x based system to do a format /s on.

25th Mar 2021, 8:10 pm	#11
Electronpusher0 Nonode Join Date: Jun 2016 Location: Bognor Regis, West Sussex, UK. Posts: 2,296	Re: GRID PSU, definitely 'Not Working' ! Are you sure that the components have been removed? Check the underside for signs of being desoldered, it may be that the components were never fitted. Its not unusual for manufacturers to use one pcb for several supplies, fitting components as required for that application. If that is the case, fitting the components could make matters worse. Peter

25th Mar 2021, 9:02 pm	#13
nigelr2000 Heptode Join Date: Nov 2008 Location: North Walsham, Norfolk, UK. Posts: 900	Re: GRID PSU, definitely 'Not Working' ! One track connects to the bottom and one to the top with the 2 connected ones adding up to 4 connections it's just the little circles missing not a track. __________________ https://www.facebook.com/gntrading

26th Mar 2021, 10:06 am	#14
Buzby123 Heptode Join Date: Oct 2011 Location: Culcheth, Cheshire, UK. Posts: 654	Re: GRID PSU, definitely 'Not Working' ! The transformer in this PSU, it's his birthday today !. Attached Thumbnails

26th Mar 2021, 4:10 pm	#15
ortek_service Octode Join Date: May 2018 Location: Northampton, Northamptonshire, UK. Posts: 1,440	Re: GRID PSU, definitely 'Not Working' ! At least they left that in there! I did wonder if the electrolytic capacitors had been removed, to get better access to the transistors, as it seems it's quite compact in there. Although from some photos it looked like these capacitors may have been low-height ones so may have not been such an obstruction / finding correct size could be a bit more involved. And they hadn't been removed too well, loosing a top & a bottom pads (plus possibly the hole's through-plating), when it's normally possibly to heat both pins at once and pull out these, without any damage.

26th Mar 2021, 4:50 pm	#16
Buzby123 Heptode Join Date: Oct 2011 Location: Culcheth, Cheshire, UK. Posts: 654	Re: GRID PSU, definitely 'Not Working' ! The 1530 has returned to the back burner !. The DS1287 was dead, that's what the Code 2 error means. So I did the 'drill hole and add new battery' hack. I presume this worked, as now there is no error code at boot up. Unfortuately the fault now reported is HDD failure, and it also it won't boot from a floppy either. I've got bigger fish to fry, so I'm leaving the faulty PSU, and faulty computer, for another day. Cheers, Buzby

26th Mar 2021, 5:15 pm	#17
ortek_service Octode Join Date: May 2018 Location: Northampton, Northamptonshire, UK. Posts: 1,440	Re: GRID PSU, definitely 'Not Working' ! (If you haven't already done it): Next time you work on it, try going into BIOS set-up and resetting to factory default / check HDD & FDD settings, as these will probably have been lost by low DS1287 battery which will also back up its 'CMOS' RAM.

26th Mar 2021, 5:21 pm	#18
Buzby123 Heptode Join Date: Oct 2011 Location: Culcheth, Cheshire, UK. Posts: 654	Re: GRID PSU, definitely 'Not Working' ! I don't know how to get into BIOS setup. If the problem is just BIOS settings I will have another go tomorrow !. Cheers, Buzby

26th Mar 2021, 6:06 pm	#19
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,560	Re: GRID PSU, definitely 'Not Working' ! On PCs of that era with typical 'AWARD' or 'Phoenix' BIOS it was common to get into the BIOS by repeatedly hitting DEL during the boot process, although laptops / portables often deviated from that because they tended to have a reduced number of keys. If you read carefully what the machine says on the screen during boot-up it will often tell you what you have to press to get into the BIOS. Last edited by SiriusHardware; 26th Mar 2021 at 6:16 pm.

26th Mar 2021, 6:31 pm	#20
SiriusHardware Dekatron Join Date: Aug 2011 Location: Newcastle, Tyne and Wear, UK. Posts: 11,560	Re: GRID PSU, definitely 'Not Working' ! I found this old mega-thread elsewhere... http://www.brutman.com/RuGRiD/RuGRiD_part2.html ...When I was trying to find out for sure how to get into the BIOS. It discusses several GRID models as it meanders but one of the surprising things which comes up - it may or may not apply to your model - is that the type of HDD fitted may be hard-coded into the BIOS as there is talk of editing the BIOS ROMs to make them work with other HDDs. If so, this is very hardcore indeed.