ID THIS CDTV Part source win a malcontent kitty!

Sandgunner · 20 September 2010, 10:31

Well I do know what the part is but for the life of me I can't find a source for it or a suitable replacement. Any thoughts from the Gurus out there?

While removing a stubborn CDTV cover it caught the edge of this Transformer
and plucked the wire spool right off the base.

It is the T1 DC/DC transformer converter that takes a 5v input and outputs two 31.5vdc lines as filament voltage VF1 and VF2 and a -30v as VPP for the CDTV's front display with associated circuity in the schematic. I only need
the Transformer.

Attached pictures of the exact part (on a good CDTV) with and without it's Ferrite cap on.

The Transformer has 9pins on the bottom aranged in an almost complete circle but according the the CDTV schematics only pins 1-3 and 6-9 are used.
Any thoughts for a supplier of the original part or a suitable replacement?
Schematic (if correct) shows the original coil and taps (T1)
Thanks,
Sandgunner

pandy71 · 20 September 2010, 11:35

Custom made? Similar transformer can be avaiable form other VFD equipped device...
i have few transformers from various STB VFD boards - they are smaller and E type.

If core is OK then try rewind this transformer. Just count turns, use similar wire.

Loedown · 20 September 2010, 14:00

I'm sure someone will have a wrecked unit they are willing to cannibalize for parts.

Sandgunner · 20 September 2010, 20:26

Quote:

Originally Posted by pandy71

If core is OK then try rewind this transformer. Just count turns, use similar wire.

Unfortunately the core was ripped off the base and although the core is still
intack there is no way to know which broken wire end went to which base pad since the base is uniform all around.

I could decontruct the good transformer(in the pic) to re-create the destroyed one but I'm chicken!
Too woried about getting the windings wrong and killing the display.

Thankfully this one part only supplies voltage for the front panel display and has no effect on the CDTV working, only
no front panel display.

If someone has a CDTV that is botched and could offer me the part please PM.
Thanks
SandGunner

pandy71 · 20 September 2010, 22:54

Just glue core, use epoxy resin it should work. It can be fixed, be patient and try understand schematic and match wires.

Whole circuit is 5V powered then to raise voltage up to the 32V You need at least 7 - 8 more turns on secondary winding than on primary winding.

Shadowfire · 21 September 2010, 03:52

Transformers usually are numbered around the edge similarly to a DIP IC (counterclockwise from pin 1). But, since pin 4 & 5 are no connects, and pin 3 is tied to +5V standby, it should be easy to deduce what pin one is, even if they didn't mark it on the silkscreen or change the pad shape for pin 1.

Sandgunner · 21 September 2010, 04:20

Ok I'm convinced to rebuild the transformer. Now I just have to find the little bugger
of the core! Misplaced it.....grrrrr. Worse case scenario if I can't find the original core I'll scavenge some other VFD for the transformer. Either case it will need rewinding anyway.

SandGunner

reinauer · 27 February 2024, 07:01

This is an interesting thread. I am at the same point and looking into options for recreating the transformer:

- try to contract out recreating the original form factor to a chinese company

What's this form factor/footprint even called? Sumida LC-128 looks as similar as I could find, physically (of course the pinout is entirely different)

- design an adapter board and use an off the shelf bobbin to wire my own transformer.

This is tricky because desoldering the original intact is almost impossible. The leads hold the wires and they rip off very easily. The plastic and glue are very heat sensitive, so it is easy to destroy the plastic bottom.

Also, counting the windings is tricky when your transformer has burned out already, you will get several pieces of wire.

- wire up VFD/VPP to 5VD and replace the front panel with something that features a microcontroller and a SPI controlled OLED.
Following this path I got as far as cloning the original front panel https://github.com/reinauer/CDTV-front-panel

I have started going down all three of these paths. Did anybody else here pursue craziness like this?

20 September 2010, 10:31	#1
Sandgunner Kill everything in a 360 Join Date: Sep 2006 Location: Near West Chester PA. Made the pilgrimage to the former Amiga assembly plant. Posts: 23	ID THIS CDTV Part source win a malcontent kitty! Well I do know what the part is but for the life of me I can't find a source for it or a suitable replacement. Any thoughts from the Gurus out there? While removing a stubborn CDTV cover it caught the edge of this Transformer and plucked the wire spool right off the base. It is the T1 DC/DC transformer converter that takes a 5v input and outputs two 31.5vdc lines as filament voltage VF1 and VF2 and a -30v as VPP for the CDTV's front display with associated circuity in the schematic. I only need the Transformer. Attached pictures of the exact part (on a good CDTV) with and without it's Ferrite cap on. The Transformer has 9pins on the bottom aranged in an almost complete circle but according the the CDTV schematics only pins 1-3 and 6-9 are used. Any thoughts for a supplier of the original part or a suitable replacement? Schematic (if correct) shows the original coil and taps (T1) Thanks, Sandgunner Attached Thumbnails

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20 September 2010, 11:35	#2
pandy71 Registered User Join Date: Jun 2010 Location: PL? Posts: 2,745	Custom made? Similar transformer can be avaiable form other VFD equipped device... i have few transformers from various STB VFD boards - they are smaller and E type. If core is OK then try rewind this transformer. Just count turns, use similar wire.

20 September 2010, 14:00	#3
Loedown Precious & fragile things Join Date: Feb 2009 Location: Victoria, Australia Posts: 1,946	I'm sure someone will have a wrecked unit they are willing to cannibalize for parts.

20 September 2010, 22:54	#5
pandy71 Registered User Join Date: Jun 2010 Location: PL? Posts: 2,745	Just glue core, use epoxy resin it should work. It can be fixed, be patient and try understand schematic and match wires. Whole circuit is 5V powered then to raise voltage up to the 32V You need at least 7 - 8 more turns on secondary winding than on primary winding.

21 September 2010, 03:52	#6
Shadowfire Registered User Join Date: Aug 2001 Location: Connecticut USA Posts: 617	Transformers usually are numbered around the edge similarly to a DIP IC (counterclockwise from pin 1). But, since pin 4 & 5 are no connects, and pin 3 is tied to +5V standby, it should be easy to deduce what pin one is, even if they didn't mark it on the silkscreen or change the pad shape for pin 1.

21 September 2010, 04:20	#7
Sandgunner Kill everything in a 360 Join Date: Sep 2006 Location: Near West Chester PA. Made the pilgrimage to the former Amiga assembly plant. Posts: 23	Ok I'm convinced to rebuild the transformer. Now I just have to find the little bugger of the core! Misplaced it.....grrrrr. Worse case scenario if I can't find the original core I'll scavenge some other VFD for the transformer. Either case it will need rewinding anyway. SandGunner

27 February 2024, 07:01	#8
reinauer Registered User Join Date: Jan 2020 Location: Mountain View, California Posts: 56	This is an interesting thread. I am at the same point and looking into options for recreating the transformer: - try to contract out recreating the original form factor to a chinese company What's this form factor/footprint even called? Sumida LC-128 looks as similar as I could find, physically (of course the pinout is entirely different) - design an adapter board and use an off the shelf bobbin to wire my own transformer. This is tricky because desoldering the original intact is almost impossible. The leads hold the wires and they rip off very easily. The plastic and glue are very heat sensitive, so it is easy to destroy the plastic bottom. Also, counting the windings is tricky when your transformer has burned out already, you will get several pieces of wire. - wire up VFD/VPP to 5VD and replace the front panel with something that features a microcontroller and a SPI controlled OLED. Following this path I got as far as cloning the original front panel https://github.com/reinauer/CDTV-front-panel I have started going down all three of these paths. Did anybody else here pursue craziness like this?

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