Hi guys,
In 2007 I bought a second-hand Sherwood TEMA A-1 and TEMA P-1 power and pre-amp combination together with an Advance MCD 203 CD-player and Paradigm speakers from Athens, Greece.
Up until this year I have been lucky enough to enjoy listening to the great sound of the TEMA amps.
Unfortunately a few months ago the TEMA A-1 stopped functioning. After a lot of work and effort I managed to figure out that there was a problem with the TOSHIBA IGBTs.
I searched in vain to find spares for these and was told that this kind of technology is now obsolete. The response to my queries from Toshiba Electronics Europe GmBH was that these are discontinued and are obsolete.
I've tried Sherwood US but they didn't seem to be able to help.
I've also tried contacting INKEL in S.Korea but they never responded.
Can anyone help me find a couple of TOSHIBA GT20D201 IGBTs?
I think that the Palmer LX 2000 PA Power Amp also had these iGBTs.
Any ideas/tips?
Many thanks
In 2007 I bought a second-hand Sherwood TEMA A-1 and TEMA P-1 power and pre-amp combination together with an Advance MCD 203 CD-player and Paradigm speakers from Athens, Greece.
Up until this year I have been lucky enough to enjoy listening to the great sound of the TEMA amps.
Unfortunately a few months ago the TEMA A-1 stopped functioning. After a lot of work and effort I managed to figure out that there was a problem with the TOSHIBA IGBTs.
I searched in vain to find spares for these and was told that this kind of technology is now obsolete. The response to my queries from Toshiba Electronics Europe GmBH was that these are discontinued and are obsolete.
I've tried Sherwood US but they didn't seem to be able to help.
I've also tried contacting INKEL in S.Korea but they never responded.
Can anyone help me find a couple of TOSHIBA GT20D201 IGBTs?
I think that the Palmer LX 2000 PA Power Amp also had these iGBTs.
Any ideas/tips?
Many thanks
Thanks a lot for the advice Rayma,
Unfortunately I haven't been able to find those Toshiba IGBTs. I bought a couple from a German spare parts dealer based in Ireland and from another site in the US but they were not Toshiba and weren't any good.
I guess that some other devices might use those and that's what I'm looking for.
Do you have any suggestions?
Cheers
Unfortunately I haven't been able to find those Toshiba IGBTs. I bought a couple from a German spare parts dealer based in Ireland and from another site in the US but they were not Toshiba and weren't any good.
I guess that some other devices might use those and that's what I'm looking for.
Do you have any suggestions?
Cheers
It appears that this part was made in several different case styles, the TO-220 and the TO-3P.
Determine which case style you need before buying any.
Some are on ebay. You may need to have a friend in the USA buy them and mail them to you,
since the first seller only ships to the USA. These sellers appear to be trustworthy.
TOSHIBA GT20D201 TO-3PL P CHANNEL TYPE (HIGH POWER RH 6240379223660 | eBay
GT20D201 Original Pulled Toshiba IGBT 20A 250V P-CHANNEL 6240379223660 | eBay
Determine which case style you need before buying any.
Some are on ebay. You may need to have a friend in the USA buy them and mail them to you,
since the first seller only ships to the USA. These sellers appear to be trustworthy.
TOSHIBA GT20D201 TO-3PL P CHANNEL TYPE (HIGH POWER RH 6240379223660 | eBay
GT20D201 Original Pulled Toshiba IGBT 20A 250V P-CHANNEL 6240379223660 | eBay
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IGBT are pretty common in variable frequency drives and power controllers, and Fairchild was a big supplier, among others.
Just do a parametric search, and put a slightly higher rated one after finding what caused it to fail.
Put 20A 250V P channel IGBT, you will find US and European matching parts, go onward from there.
Just do a parametric search, and put a slightly higher rated one after finding what caused it to fail.
Put 20A 250V P channel IGBT, you will find US and European matching parts, go onward from there.
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In general IGBTs are more efficient at high voltage, not necessarily high power, since they have a fixed Vsat (rather than an on-resistance). This is also why they generally come in only 600V and 1200V ratings.
For <=50V high power MOSFETs will be loads more efficient than IGBTs (and run at higher switching frequencies meaning smaller caps and inductors).
IGBTs typically have Vsat in range 1.5 to 2.5V. MOSFETs are available down to 0.0001 ohm on-resistance or so (for low voltages), but for higher voltage the on-resistance becomes larger and larger (to several ohms for really high voltage parts).
Just compare to equivalents why these were used in this application, it is not a regular use. Maybe a difference in frequency, trigger voltage, something...
And read the thread I linked to, that might give you an understanding of what is going on.
It may be possible to convert the circuit to ordinary Mosfets, but that is only a thought from my side.
And read the thread I linked to, that might give you an understanding of what is going on.
It may be possible to convert the circuit to ordinary Mosfets, but that is only a thought from my side.
Please, no guesswork about availability or possible replacements
from people who have never seen or used Toshiba IGBTs.
from people who have never seen or used Toshiba IGBTs.
It is an odd use.
Maybe he can read the Elektor article to understand.
I have used Toshiba IGBTs in repairing thread tensioning machines and winders...it is very unusual as an audio component.
You are saying no guesses, so please share your knowledge about this topic and application.
Maybe he can read the Elektor article to understand.
I have used Toshiba IGBTs in repairing thread tensioning machines and winders...it is very unusual as an audio component.
You are saying no guesses, so please share your knowledge about this topic and application.
Looks like we are looking at just one channel there?, with six P channel on the top row and six complementary on the bottom row of the heatsink
Quite the beast😀
I see these on ebay (green ones too so more chance of them being genuine ... he said with tongue slightly in cheek)
eBay item number:
262552653930
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Just what is the rated power?
Do you need that much power?
Do you have schematic?
What was the problem with substitutes?
Why only P channel?
Just how many do you need?
Meanwhile, get or make a smaller amplifier for home use, 20A x 250V x 6 is 30kW!
That is Sydney Opera House size output...
Do you need that much power?
Do you have schematic?
What was the problem with substitutes?
Why only P channel?
Just how many do you need?
Meanwhile, get or make a smaller amplifier for home use, 20A x 250V x 6 is 30kW!
That is Sydney Opera House size output...
These original Toshiba devices have been long discontinued. I think these parts were designed with characteristics useful for audio applications versus the usual focus on switching applications, so finding a modern part equivalent replacement is VERY unlikely. Personally, I wouldn't buy semiconductors from eBay, but that's an individual's personal decision. Although it sounds painful, I would consider changing the amp design to use MOSFETs instead. By the way, I think some early adopters of these particular IGBTs for audio amps found that they had latch-up issues. Maybe Mr Pass will wander over and make a comment; I think he played around with them back in the day.
Good luck with whatever decision you make!
Good luck with whatever decision you make!
The drive for these is different from Mosfets...
But in long run it is necessary, as one of the failure mechanisms of IGBTs is ageing.
So the long term solution is building another output stage, and possibly an intermediate stage, salvaging the power supply and housing.
And the pre amp, selector and so on.
And this will stay an obscure step in evolution, like the DeLorean cars...
But in long run it is necessary, as one of the failure mechanisms of IGBTs is ageing.
So the long term solution is building another output stage, and possibly an intermediate stage, salvaging the power supply and housing.
And the pre amp, selector and so on.
And this will stay an obscure step in evolution, like the DeLorean cars...
I’ve been stung a couple of times with semis on eBay, just take a VERY close look at the devices when you get them.
The legs should be sans solder obviously, I’ve had quite a few with new cold welded/pressed legs attached very close to the encapsulation , quite obvious when you spot it.
PayPal will have your back when you challenge they’re not new or as above/salvaged(or fakes) with new legs.
So you’re safe enough.
Try some acetone on a cotton bud on the writing to see if they’re been rebadged/rewritten.
And lastly stick the new ones on a component tester like a peak and compare the results with some working examples off your amp
Actually, just a thought:
Would it be possible to drive switching transistors through a Class D amp to use as a final stage?
This seems to be the technique used here...or a variation.
A new thread then...
Would it be possible to drive switching transistors through a Class D amp to use as a final stage?
This seems to be the technique used here...or a variation.
A new thread then...
These were used at Threshold when I was there and Toshiba discontinued them as you know. They are rather specialized and modern IGBT's are not offered in P channel versions. My stash is unfortunately gone and your best bet would be conversion to MOSFET but a rather large project.
While offering easy drive and low output impedance they also oscillated and had thermal runaway, the best and worst of both devices. If not designed carefully they would self destruct. This might be why they didn't last on the market.
While offering easy drive and low output impedance they also oscillated and had thermal runaway, the best and worst of both devices. If not designed carefully they would self destruct. This might be why they didn't last on the market.