Fw: [vintagesynthrepair] Alesis ion Q01 - power supply
2016-05-30 by Cosmic Fugue
Forgot to mention the mains supply here is high at 240VAC ----------------------------------------------------------------------------- Originally I found: F1=T1A o/c, Q2=TOP223Y s/c – primary side, D3=1N5822 s/c – secondary side Fitted new fuse & diode and replaced Q2 with TOP224Y It worked for about 2 to 3 days then as soon as I went to switch on again, heard a noise and Q2 went faulty again although this time found F1 still ok. Wasn’t sure if fitting a 224 was ok although I knew it handled more current from the specs. Then ordered a complete power supply but its taking months for it to arrive. In the mean time I found a TOP223Y from a scrap DVD player power supply. Fitted this in but took care for a possible dry joint or bad connection especially primary side Q2 circuit area. It is now working ok however I noted its working temperature too high... and no heat-sink. But then again years back I bought a 14” CRT TV and when I opened it to see how it was made I couldn’t help to notice either the SMPS chopper transistor or the HOT (I don’t remember exactly and have to open set to verify) that had no heat-sink (guess why..?). First thing I did was fit a proper heat-sink. Few months later an exact TV model like mine came in for repair and guess which transistor went duff? I couldn’t help to notice over the years that they had started to eliminate heat-sinks + + etc... with various equipment like Video Recorders etc... But then I thought, not too bad for us, though I wouldn’t say BIG, rather ‘some’ bucks for us, for a change! Once again thank you for your help and interest.
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From: mailto:vintagesynthrepair@yahoogroups.com
Sent: Monday, May 30, 2016 12:44 AM
To: vintagesynthrepair@yahoogroups.com
Subject: Re: [vintagesynthrepair] Alesis ion Q01 - power supply
Probably normal and just doing a little too much work. Often engineers design for potential low line voltage conditions (90 to 95 V), but with the normal or higher, the regulator must now drop more voltage across it, more Watts, more heat.
I would calculate the work(voltage drop x current) that it is handling against the specs sheet for that transistor. Then again, it seems like most of the Alesis repairs that I have done often involve a shorted or partially shorted cap, which would draw more current and run hotter.
Yea, this is why we get those BIG bucks!
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On Fri, 5/27/16, Cosmic Fugue cosmicfugue@... [vintagesynthrepair] <vintagesynthrepair@yahoogroups.com> wrote:
Subject: Re: [vintagesynthrepair] Alesis ion Q01 - power supply
To: vintagesynthrepair@yahoogroups.com
Cc: winking_n_nodding@...
Date: Friday, May 27, 2016, 5:13 AM
I haven’t measured its
temperature as I do not
have this meter.
As soon as I switch off
and touch it for 2
seconds I do not burn my finger
but wasn’t able to keep
it on it either as it was
too hot.
I have now fitted the
replacement with a small
heat-sink but just the same it works too hot.
Thanks for you
help...
From: mailto:vintagesynthrepair@yahoogroups.com
Sent: Thursday, May 26, 2016 10:05 PM
To: vintagesynthrepair@yahoogroups.com
Subject: Re: [vintagesynthrepair] Alesis ion Q01
- power
supply
How hot is it? 70C? 80C? Warm to hot is normal, burn
fingers in 2 seconds is
not.
--------------------------------------------
On Wed, 5/18/16, Cosmic
Fugue cosmicfugue@... [vintagesynthrepair]
<vintagesynthrepair@yahoogroups.com> wrote:
Subject:
[vintagesynthrepair] Alesis ion Q01 - power supply
To:
vintagesynthrepair@yahoogroups.com
Date:
Wednesday, May 18, 2016, 5:25
AM
Anyone
has or has met
with an Alesis ion
(Q01)?
I noted Q2=TOP223Y in
the
primary of SMPS runs
extremely hot (caution: switch off!!)
Is this
normal? It has
no
heat-sink!
cosmo
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