Re: Question re TL 922 amplifier

[Antonio Vernucci]

> A second option exists. When you first power up the 922 don't panic over the
> current being drawn and jump to turn it off. Wait for 10 to 15 seconds to see
> if the filament heating and resultant thermal expansion will eliminate the
> short for you.

Very dangerous with the TL-922. Due to Kenwood design fault, the 80V service
voltage gets shorted to ground when a grid-to-filaments occurs. After a short
while the service transformer (T2) will be permantly damaged.

73

Tony I0JX

[Scott Dorsey]

Antonio Vernucci > wrote:
>> A second option exists. When you first power up the 922 don't panic over the
>> current being drawn and jump to turn it off. Wait for 10 to 15 seconds to see
>> if the filament heating and resultant thermal expansion will eliminate the
>> short for you.
>
>Very dangerous with the TL-922. Due to Kenwood design fault, the 80V service
>voltage gets shorted to ground when a grid-to-filaments occurs. After a short
>while the service transformer (T2) will be permantly damaged.

Agreed. However, sometimes shock and vibration can rattle the whiskers
off the grids. Pull the tubes and let them roll around on the floor of
your car for a couple weeks; this may help you get a little more lifetime
out of them.

Be really careful with the things, though.... the transformer damage issue is a
big deal.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[Dave]

Antonio Vernucci wrote:

>> A second option exists. When you first power up the 922 don't panic
>> over the current being drawn and jump to turn it off. Wait for 10 to
>> 15 seconds to see if the filament heating and resultant thermal
>> expansion will eliminate the short for you.
>
>
> Very dangerous with the TL-922. Due to Kenwood design fault, the 80V
> service voltage gets shorted to ground when a grid-to-filaments occurs.
> After a short while the service transformer (T2) will be permantly damaged.
>
> 73
>
> Tony I0JX

Thanks Tony for that information. I was unaware of that design in the 922. I run
Ameritron stuff.

But, poping the fuze is still worth a try. You do have to remove the 3-500 from
the amplifier to pop the fuze.