Where can I find a replacement EHT diode ?

[Nick]

My Gould scope has died, it seems that the EHT supply has died. This is a
2.5kV rail supplied from a 950V secondary and a charge pump. The diodes
appear to be blown (I set my variable PSU current limit to 20mA then wound
up the voltage to measure Vf - the PSU goes up to 30V, there can't be THAT
many junctions in a package 10mm long!)

The scope manual lists them as "IJK60TR 6kV"

Some Googling suggests FM50 or SL1200, but I can't find them either. In fact
diodes with this voltage rating seem quite rare. I know I could stack some
lower voltage diodes (and bleed resistors) but space is a bit limited.

Can anyone suggest a replacement, or supplier in the UK?

Thanks
Nick

 

[N Cook]

My Gould scope has died, it seems that the EHT supply has died. This is a
2.5kV rail supplied from a 950V secondary and a charge pump. The diodes
appear to be blown (I set my variable PSU current limit to 20mA then wound
up the voltage to measure Vf - the PSU goes up to 30V, there can't be THAT
many junctions in a package 10mm long!)

The scope manual lists them as "IJK60TR 6kV"

Some Googling suggests FM50 or SL1200, but I can't find them either. In fact
diodes with this voltage rating seem quite rare. I know I could stack some
lower voltage diodes (and bleed resistors) but space is a bit limited.

Can anyone suggest a replacement, or supplier in the UK?

Thanks
Nick

Don't replace with seriesed high current diodes, part of the function of
these diodes seems to be a fuse to protect transformer over-windings from
downstream problems.

 

[Baron]

My Gould scope has died, it seems that the EHT supply has died. This
is a 2.5kV rail supplied from a 950V secondary and a charge pump.
The diodes appear to be blown (I set my variable PSU current limit
to 20mA then wound up the voltage to measure Vf - the PSU goes up to
30V, there can't be THAT many junctions in a package 10mm long!)

The scope manual lists them as "IJK60TR 6kV"

Some Googling suggests FM50 or SL1200, but I can't find them either.
In fact diodes with this voltage rating seem quite rare. I know I
could stack some lower voltage diodes (and bleed resistors) but
space is a bit limited.

Can anyone suggest a replacement, or supplier in the UK?

Thanks
Nick

That IJK60TR part no: sounds a bit microwave oven'ish.

 

[t w]

My Gould scope has died, it seems that the EHT supply has died. This is a
2.5kV rail supplied from a 950V secondary and a charge pump. The diodes
appear to be blown (I set my variable PSU current limit to 20mA then wound
up the voltage to measure Vf - the PSU goes up to 30V, there can't be THAT
many junctions in a package 10mm long!)

The scope manual lists them as "IJK60TR 6kV" Try MARK5

Some Googling suggests FM50 or SL1200, but I can't find them either. In
fact
diodes with this voltage rating seem quite rare. I know I could stack some
lower voltage diodes (and bleed resistors) but space is a bit limited.

Can anyone suggest a replacement, or supplier in the UK?

Thanks
Nick

 

[t w]

My Gould scope has died, it seems that the EHT supply has died. This is a
2.5kV rail supplied from a 950V secondary and a charge pump. The diodes
appear to be blown (I set my variable PSU current limit to 20mA then wound
up the voltage to measure Vf - the PSU goes up to 30V, there can't be THAT
many junctions in a package 10mm long!)

The scope manual lists them as "IJK60TR 6kV"

Some Googling suggests FM50 or SL1200, but I can't find them either. In
fact
diodes with this voltage rating seem quite rare. I know I could stack some
lower voltage diodes (and bleed resistors) but space is a bit limited.

Can anyone suggest a replacement, or supplier in the UK?

Thanks
Nick Try MARK5

 

[Cheemag]

Try MARK5

He meant to say: http://www.mark5.co.uk/search.php

Search for 'rectifier'. Pages of 'em; all sorts of voltages .....

 

[t w]

He meant to say: http://www.mark5.co.uk/search.php

Search for 'rectifier'. Pages of 'em; all sorts of voltages .....

Sorry & yes. I've found them very helpful

 

[Nick]

Sorry & yes. I've found them very helpful

Thanks both, interesting site. One component seems to fit the bill
(SKV1/2B3000/2700-1.2) though it's listed as POA. I'll give them a call on
Monday. I just hope they're not a silly price or minimum order qty as I can
get a replacement 'scope for 75 quid...

Nick

 

[Cheemag]

Thanks both, interesting site. One component seems to fit the bill
(SKV1/2B3000/2700-1.2) though it's listed as POA. I'll give them a call on
Monday. I just hope they're not a silly price or minimum order qty as I can
get a replacement 'scope for 75 quid...

If that fails, then you can try the string of diodes suggested further
up the log. Should work.

 

[John Robertson]

My Gould scope has died, it seems that the EHT supply has died. This is a
2.5kV rail supplied from a 950V secondary and a charge pump. The diodes
appear to be blown (I set my variable PSU current limit to 20mA then wound
up the voltage to measure Vf - the PSU goes up to 30V, there can't be THAT
many junctions in a package 10mm long!)

The scope manual lists them as "IJK60TR 6kV"

Some Googling suggests FM50 or SL1200, but I can't find them either. In fact
diodes with this voltage rating seem quite rare. I know I could stack some
lower voltage diodes (and bleed resistors) but space is a bit limited.

Can anyone suggest a replacement, or supplier in the UK?

Thanks
Nick

If all else fails find an old 1970s B&W TV and steal it's HV inline
diode (LOPT HV diode to you folks across the pond). Or an early
computer green screen monitor.

John :-#)#
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