[AMPS] Re: TL 922 and burned grid choke

[km1h @ juno.com]

On Tue, 02 Dec 1997 11:39:20 -0800 OLYMPUS Support Group
<carsten.esch@olympus-software.com> writes:
>Hi,
>
>a few weeks ago you where so kind to give me some advice on how to 
>find
>a 'bug' in a TL-922. I found a defective grid choke, but after I
>replaced it last friday, still the same problem occures. Two of you
>(sorry I can not see from my summery who this was...) stated mesuring
>the choke to ground should result in about 20 Ohms. Now that I 
>replaced
>the defective choke, the amp is still not running but I measure about
>3.2 Ohms (If I remember right the paralled R is 47K and the choke is < 
>4
>Ohms) How did you get these 20 Ohms?

I certainly did not suggest 20 Ohms Carsten; that is almost correct for
the SB-220 but the TL-922 choke has a much higher current rating and
therefore a lower resistance. I measure 4.6 and 9.2 Ohms on two versions
here.  A choke that has shorted internal turns may still measure very
close to the correct value. 

I do not remember your original problem but a tube failure in the TL-922
often destroys the bias zener and the bias supply electrolytic capacitor.

73  Carl  KM1H


>
>Thank you very much,
>
>Carsten, DL6LAU
>

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