VOGONS


First post, by Grub3r

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Hi guys and gals.

I have probably fried my 88pro US version.

I got one and I bought a converter from 220-110 to use it in europe.

hooked it up and it worked for 20 min before it began to smoke.
I immediately turned it off, dissasembled and saw that one capacitor had leaked a little and spraying some acid on the pcb above it.

the unit was quite warm in area of the capacitor.
Inspected the unit and could not see any damage neither any bad smell.

I noticed the 100v(soldered) 120v 230v 240v on the transformator.
I also found the thread about convertion of sc-88pro

so the question, did unit collapsed because of the 110v delivered and not the intended 100v?
May the unit have lived on 230(because of the possible faulty converter) for 20 min?
how much damage can it have received? any change that it has survived the accident?
is there any point in soldering over to 230 and trying it again?

attached the picture, the capacitor which leaked is the one marked red.

any help is appreciated.
Thanks.

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Last edited by Grub3r on 2018-01-23, 11:21. Edited 1 time in total.

Reply 2 of 16, by Jepael

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There are also voltage converters that are meant for a bit heavier loads so it is possible your converter has put out significantly larger voltage to this low power load and the cap vented because of overvoltage. It looks like there is no other damage. It could have been due to old age as well, but seriously I'd check the converter.

Reply 3 of 16, by Grub3r

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derSammler wrote:

Just replace the cap and the unit should be fine. It most likely just failed because of age.

110v vs. 100v should not be an issue.

Jepael wrote:

There are also voltage converters that are meant for a bit heavier loads so it is possible your converter has put out significantly larger voltage to this low power load and the cap vented because of overvoltage. It looks like there is no other damage. It could have been due to old age as well, but seriously I'd check the converter.

the converter says it can deliver/handle 1865 Watts and it was dead cold in the whole process.
it also has a fuse which is fine.

the picture is borrowed so you cannot see the damaged cap as it is now, it has bulged just a little bit.
I have yet to check the underside of the pcb the cap it sitting on.

So you saying is that I may with no fear solder to 230 and try to fire it up?
or should the cap be replaced before doing anything else?

thanks.

Reply 4 of 16, by Grub3r

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the reason I ask is that I dont have skills nor precision soldering equipment for this kind of job.

soldering over to 230 should not be a problem with almost any regular iron which I can manage.

Reply 5 of 16, by derSammler

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Yes, you can also move the black wire from 100 to 240v to convert the unit to 230/240v. Did that in the past with several units. One big advantages of transformer-based PSUs.

The cap must be replaced first, however. You may want to replce the other big ones too, while you are at it anyway.

Reply 6 of 16, by Grub3r

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derSammler wrote:

Yes, you can also move the black wire from 100 to 240v to convert the unit to 230/240v. Did that in the past with several units. One big advantages of transformer-based PSUs.

The cap must be replaced first, however. You may want to replce the other big ones too, while you are at it anyway.

right.
why not 230, which is between the 220 and 240?
isnt the 240 almost absolete around the world?

thanks.

Reply 7 of 16, by derSammler

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240v is used in the UK. This setting works with 230v as well (gives lower output then, not higher). Vice-versa would not work, so this is just how it must be without having another setting for UK.

Reply 8 of 16, by Grub3r

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derSammler wrote:

240v is used in the UK. This setting works with 230v as well (gives lower output then, not higher). Vice-versa would not work, so this is just how it must be without having another setting for UK.

Im not sure I understand.

correct me if Im wrong but

we are talking about voltage and not current which is fine if its higher.

the transformator specifically defines 230 and 240.
isnt giving lower voltage will not be enough to power an equipment and giving higher voltage will be too much and result in components burnt?

Reply 10 of 16, by derSammler

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If you set the transformer to 240v but only feed it with 230v, the output voltage is slightly lower and the converter will have to turn less overvoltage into heat, extending lifetime. And it will work with 240v as well.

Reply 11 of 16, by Grub3r

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derSammler wrote:

If you set the transformer to 240v but only feed it with 230v, the output voltage is slightly lower and the converter will have to turn less overvoltage into heat, extending lifetime. And it will work with 240v as well.

ok, I just got aware that this was not the output side but input side.
thanks for the clarification.

Reply 12 of 16, by Jepael

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Grub3r wrote:

the converter says it can deliver/handle 1865 Watts and it was dead cold in the whole process.
it also has a fuse which is fine.

I think you misunderstood me. What I mean is that your converter is capable of powering high-power loads such as hairdryers and will give them the correct 110V voltage, but when you have a low power load like the SC-55 it might not convert the voltage down properly and give overvoltage to light loads. I don't know what kind of converter you have, that's why I asked you to make sure you have the correct kind of converter that will work correctly with low powered sensitive electronics, not a converter that works properly only with high powered hairdryers.

So don't use the converter unless you know it can be used with low power electronics, it might be the reason the cap blew up.

Grub3r wrote:

So you saying is that I may with no fear solder to 230 and try to fire it up?
or should the cap be replaced before doing anything else?

You must replace the cap and then you can move the wire from 110V to 230V or 240V whichever you think is best in your country.

Grub3r wrote:

why not 230, which is between the 220 and 240?
isnt the 240 almost absolete around the world?

.

Not really. 230V was made as a standard with so large tolerance that countries with 220V and 240V can just keep having 220V and 240V as long as they are within tolerance of the new 230V standard.

Grub3r wrote:

the transformator specifically defines 230 and 240.
isnt giving lower voltage will not be enough to power an equipment and giving higher voltage will be too much and result in components burnt?

Kind of, but the difference is way smaller than with incorrect voltage converter - only about 5%. Most likely it does not make a huge difference which one you use. I'd select 230V because then it can be used in 220V and 240V countries. If you wire it to 240V, then the voltage might be too low in 220V country. UK should have 230V +10%/-6%.
The SC-88 has a linear power supply, so having a bit higher voltage is not fatal. The unregulated 5V supply has 16V capacitors and unregulated +/- 12V supplies have 25V capacitors, so those are the hard max peak voltage limits. And it will still work if unregulated 5V supply dips to 5.5V and unregulated 12V supply dips to 14V. There is no mention what the transformer output AC voltages are.

Reply 13 of 16, by derSammler

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Jepael wrote:

UK should have 230V +10%/-6%.

You are right. Seems like they changed that in 1987 from 240v to 230v. In Germany, they went from 220v to 230v around the same time.

Anyway, I'd still say 240v is the correct choice. This is what people also do when maintaining the Commodore 1541 disk drive. The lesser heat dissipation only has advantages and the converter won't care about a few millivolt less anyway.

Reply 14 of 16, by Grub3r

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Hi again and happy new year to you all!

I've managed to replace the cap(s)(both 1000mf/25v and single 3300/16v) and also soldered over to 230v on the transformator to be able to use it directly in wall-outlet here in Norway.

But one last question remains before I plug it in for testing.(as Im fxxxing scared to shit in plugging it in)

As mentioned before this unit has US origins. It has some markings about cold/hot on the incoming AC on the switchboard.
the cord has 2 connectors which are both alike.(no difference in side as on some US equipment) so I need to use small US->EU adapter
I was wondering if there is any difference on which way it is plugged into the socket?

Thanks

Reply 15 of 16, by Ozzuneoj

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Grub3r wrote:
Hi again and happy new year to you all! […]
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Hi again and happy new year to you all!

I've managed to replace the cap(s)(both 1000mf/25v and single 3300/16v) and also soldered over to 230v on the transformator to be able to use it directly in wall-outlet here in Norway.

But one last question remains before I plug it in for testing.(as Im fxxxing scared to shit in plugging it in)

As mentioned before this unit has US origins. It has some markings about cold/hot on the incoming AC on the switchboard.
the cord has 2 connectors which are both alike.(no difference in side as on some US equipment) so I need to use small US->EU adapter
I was wondering if there is any difference on which way it is plugged into the socket?

Thanks

If the connector isn't polarized (two different sized connectors), then no it shouldn't make a difference.

I don't want this to rest on me though, so I'd recommend waiting for another comment from someone who has used a US -> EU adapter though, as I have not.

EDIT: Removed the link I posted because I read into it a bit more and realized there was some incorrect information and just general inaccuracy. Probably not the best source of information on what effect polarity has on electronic devices (basically, none).

Last edited by Ozzuneoj on 2018-01-11, 18:16. Edited 1 time in total.

Now for some blitting from the back buffer.

Reply 16 of 16, by Grub3r

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No, the cord is not polarized (both connectors are same size)

I also think it should not matter as AC is converted to DC in the transformer and thus no need for difference in polarity like in toaster or bulb which uses direct AC.

If that what you say i true, I then can replace the power cord altogether to reflect the EU outlet.

anyone?