My Toshiba HX-10 gets mighty hot!

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By Colemu

Champion (491)

Colemu's picture

07-12-2016, 20:38

As the topic says, my MSX1 gets really hot and I therefore don't like to use it for too long.

I bit the bullet and opened it up to see where the heat is generated, and (as you probably guessed) it's coming from the voltage regulator.

Can these things be replaced with modern hardware that runs cooler?

If so, anyone know which one would be suitable for the HX-10?

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By gdx

Paragon (1602)

gdx's picture

08-12-2016, 08:54

I noticed the same thing especially with the CF interface and an memory expansion inserted at same time. One of the two voltage regulator without heatsink is particularly hot. So as a precaution I took 2 heat sinks for SDRAM and drilled a hole to fix them. So I took 2 heat sinks for SDRAM and drilled a hole to fix one on each regulator. I also put a thin layer of thermal paste.

There is little space (see picture):
http://www.msxvillage.fr/forum/topic.php?id=2418&pt=1#m56239

By NYYRIKKI

Enlighted (4696)

NYYRIKKI's picture

08-12-2016, 10:35

picoPSU?

By RetroTechie

Paragon (1414)

RetroTechie's picture

08-12-2016, 11:23

Colemu wrote:

I bit the bullet and opened it up to see where the heat is generated, and (as you probably guessed) it's coming from the voltage regulator.


Which
part? Please be specific! ICxx, TRxx, ... (silkscreen marking on the board). Is that the part attached to alu heatsink? And it would help if you could post the markings on that part itself (and/or a photo) so that we know what to look for as replacement.

Is the machine heating overall the problem, or just the temperature of that part?

Quote:

Can these things be replaced with modern hardware that runs cooler?

Yes. Answering above questions will help us point you in the right direction.

By Colemu

Champion (491)

Colemu's picture

08-12-2016, 13:30

Hi RetroTechie,

I wanted to post the part number (it's the one next to the Transformer and attached to the Aluminium heat sink, but the markings are obscured by a large capacitor.

I will have to remove the capacitor to see the part number and get back with the details.

The rest of the machine stays relatively cool, but with the case closed that part heats up the machine as a whole. So much as to deter me from using it in fear it will die...

Tried to make out markings:
T
?435

? could be a 8, B maybe

I'm working the next couple of days, so will get the part number and a photo this weekend.

Thanks again!

By gdx

Paragon (1602)

gdx's picture

08-12-2016, 14:37

The regulator with the large aluminum heatsink also heats. I thought to replace the heat sink by another of the same size but black and with more fins for a better thermal performance. I not found.

By Colemu

Champion (491)

Colemu's picture

08-12-2016, 14:39

gdx wrote:

The regulator with the large aluminum heatsink also heats. I thought the replacement of the heat sink by another of the same size but black and with more fins for a better thermal performance. I not found.

Yeh, thats the one I'm talking about. That heatsink gets 'mad hot' and acts like a heater for the entire machine. I know the VDP etc get hot anyway, and having a hot machine will make things even worse. Heat = Kills IC's

I wondered if I could ditch the old Voltage Regulator and replace with something that doesn't generate as much heat. I would then feel more comfortable using the machine for longer periods. Can you make out the markings on the Voltage Regulator attached to the Aluminium heatsink? Mine are faint and obscured by the capacitor?

By RetroTechie

Paragon (1414)

RetroTechie's picture

08-12-2016, 15:56

Can you see how the part is "named" according to silkscreen marking on the board?

Also: do you have a voltmeter? If so: find a 0V (Ground) point, and measure voltage on each of the pins of that part. Results may give us some clues what we're looking at, for example whether it's a plain 78xx 7805 regulator, or a power transistor.

By Lord_Zett

Paladin (801)

Lord_Zett's picture

08-12-2016, 16:16

msx is realy hot. yeah touch my msx!

By tvalenca

Hero (660)

tvalenca's picture

08-12-2016, 22:15

According to @sd_snatcher, most Toshibas have underengeneered PSUs. This means that some components on those PSUs are working at the limit, including the internal transformer. The best way to work this around is to replace all the heat spreaders on the bigger transistors with bigger ones, install heat spreaders on those bigger transistors which don't have any heatspreader, and place a small fan blowing cold air over the transformer/transistor heatspreaders. These modifications will cool down the machine, and will make safer to plug them on voltages up to 127V (like we have on some regions here in Brazil)

more advanced users could replace the power transformer (desired if anyone wants to run directly at 220-240V), but transformer secondary parameters were still unknown last time I checked. And if you are planning to rewind its first stage, the core isn't safe for that much current without proper cooling, so you'll need a case fan anyway. (a small switching PSU would require it along with proper grounding aswell)

By gdx

Paragon (1602)

gdx's picture

09-12-2016, 01:13

There is no reason to change the transformer except when the varnish gets too old.
The European HX-10 are already 220-240V. If you use a Japanese HX-10, You must use an AC adapter to 100V with a power more than 30W.

Changing the regulator that heats up the most is a good idea. It is necessary to know the reference of the component and to take another one of higher intensity. I do not know if the service manual is available.

I recommend taking like me waiting for something better. I think both regulators without radiator are for the +12V and -12V because my memory expansion is the MMM, the version that use these tensions. FM-PAC and some other cartridges also use these tensions.

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