No HV on tek 465


magaudiolab
 

Hi all,
my tek 465 suddenly stopped working... The problem is clearly on HV circuitry since there is no HV at all.

After some checking I found that at least CR1421 was broken (open diode).
It is a Varo vg12x diode (1200V, 5mA, max fwd 30V) but I have found no equivalent around the web.

Can someone help me?


Thanks


Jerry Massengale <jmassen418a@...>
 

Hi,
 
See 160558092700 on feebay.
 
jerry



-----Original Message-----
From: magaudiolab
To: TekScopes
Sent: Sat, Jul 2, 2011 11:38 am
Subject: [TekScopes] No HV on tek 465

 
Hi all,
my tek 465 suddenly stopped working... The problem is clearly on HV circuitry since there is no HV at all.

After some checking I found that at least CR1421 was broken (open diode).
It is a Varo vg12x diode (1200V, 5mA, max fwd 30V) but I have found no equivalent around the web.

Can someone help me?

Thanks


Mendel Pearl <mypearl@...>
 

I can send you one for free, but I am in Holland. I think it will fit a standard letter so cost should be no issue.

Let me know if you want one.

Mendel

On 2-7-2011 18:38, magaudiolab wrote:
Hi all,
my tek 465 suddenly stopped working... The problem is clearly on HV circuitry since there is no HV at all.

After some checking I found that at least CR1421 was broken (open diode).
It is a Varo vg12x diode (1200V, 5mA, max fwd 30V) but I have found no equivalent around the web.

Can someone help me?


Thanks




------------------------------------

Yahoo! Groups Links




 

--- In TekScopes@..., "magaudiolab" <v.maglietta@...> wrote:

Hi all,
my tek 465 suddenly stopped working... The problem is clearly on HV circuitry since there is no HV at all.

After some checking I found that at least CR1421 was broken (open diode).
It is a Varo vg12x diode (1200V, 5mA, max fwd 30V) but I have found no equivalent around the web.

Can someone help me?


Thanks
------
How did you determine it was open ? This diode (152-0409-00) has forward
drop of about 9 V at 1 mA so it can not be checked with a normal DMM.
/Håkan


J. L. Trantham
 

When I have tested similar diodes (although lower voltage, about 5 KV) I had to use a power supply through a resistor to drive the diode forward to see the current flow since my DMM couldn't produce enough forward voltage to 'turn on' the diode.  Which DMM are you using?
 
Joe
 
 

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Hakan H
Sent: Saturday, July 02, 2011 5:07 PM
To: TekScopes@...
Subject: [TekScopes] Re: No HV on tek 465

 



--- In TekScopes@..., "magaudiolab" wrote:
>
> Hi all,
> my tek 465 suddenly stopped working... The problem is clearly on HV circuitry since there is no HV at all.
>
> After some checking I found that at least CR1421 was broken (open diode).
> It is a Varo vg12x diode (1200V, 5mA, max fwd 30V) but I have found no equivalent around the web.
>
> Can someone help me?
>
>
> Thanks
> ------
How did you determine it was open ? This diode (152-0409-00) has forward
drop of about 9 V at 1 mA so it can not be checked with a normal DMM.
/Håkan


 

--- In TekScopes@..., "J. L. Trantham" <jltran@...> wrote:

When I have tested similar diodes (although lower voltage, about 5 KV) I had
to use a power supply through a resistor to drive the diode forward to see
the current flow since my DMM couldn't produce enough forward voltage to
'turn on' the diode. Which DMM are you using?

Joe

-------
576 curve tracer
/Håkan


J. L. Trantham
 

Oh.
 
Joe
 
 

-----Original Message-----
From: TekScopes@... [mailto:TekScopes@...] On Behalf Of Hakan H
Sent: Sunday, July 03, 2011 4:05 AM
To: TekScopes@...
Subject: [TekScopes] Re: No HV on tek 465

 



--- In TekScopes@..., "J. L. Trantham" wrote:
>
> When I have tested similar diodes (although lower voltage, about 5 KV) I had
> to use a power supply through a resistor to drive the diode forward to see
> the current flow since my DMM couldn't produce enough forward voltage to
> 'turn on' the diode. Which DMM are you using?
>
> Joe
>
> -------
576 curve tracer
/Håkan


magaudiolab
 

--- In TekScopes@..., "Hakan H" <hahi@...> wrote:



--- In TekScopes@..., "magaudiolab" <v.maglietta@>
How did you determine it was open ? This diode (152-0409-00) has forward
drop of about 9 V at 1 mA so it can not be checked with a normal DMM.
/Håkan
Hi Håkan,
I did not use DMM at all, but a D-R series circuit (R being 22k so current max should never exceed 3mA) powered by a variable power supply (up to 60V).
Diode never showed any measurable conduction at all. If any, current is below .01uA.
Far way from 9V @ 1mA as you stated.
If it is not opened, it is likely to be a leaky diode.


magaudiolab
 

Thank you so much Mendel!
I am still checking HV (hoping to find my good old HV probe ASAP. I had one in my lab but I have not used it for so long... God knows where is it now!).
I will use 2CL73 (easy to find) which seems a valid alternative, if it should work I will let to know.

Valerio

--- In TekScopes@..., Mendel Pearl <mypearl@...> wrote:

I can send you one for free, but I am in Holland. I think it will fit a
standard letter so cost should be no issue.

Let me know if you want one.

Mendel