On 30 Jul 2006 23:27:28 -0700, "reario"
put finger to keyboard and composed:
GPG wrote:
reario wrote:
I'm trrying to repair an old Sony 21" BE-1 TVC that presents no audio
at all.
I replaced the IC TDA1013A with a new TDA1013B with the following
results: audio now is ok but when TV is off for a long period (several
hours) it comes out after severals seconds 
.
The second stage of the IC TDA1013A|B (an AF ampli that drives 8ohm
speaker) works fine because if I inject the signal on pin 5 sound is
ok (the problem is that in this way I bypass the pre-ampli stage that
has VAC for volume control).
Is There something I can do in order to get IC 1013B compatible with IC
1013A? I'm not able to retreive the TDA1013A in the marketing...
Thanks,
There is no electrical difference between them. Check pin7 voltage, 2V
= low, 6V = high vol
hi, thanks for your answer. I've checked all voltages on IC and
everything seems to be ok.
with multimeter on pin pin7 the output ranges from 3V to 6.5V. Mute
works fine (when I disconnect RF signal or local video input) voltage
on pin7 drops to 2.9V). Our Sony technical supports says that
ICTDA1013A and tda1013B have different input and output impedence so
the RC network presents in the TVC is optmal for the 1013A model.
It is not possible to get a version of IC 1013A in pour market (Italy).
Thanks again, Vittorio
I found these datasheets:
http://www.semiconductors.philips.co...otes/AN148.pdf
http://www.semiconductors.philips.co...013B_CNV_2.pdf
The TDA1013A has an input impedance of 100K whereas the TDA1013B has
an Rin of 29K. AFAICS, this difference should only be important if the
output impedance of the sound IF stage is of comparable magnitude.
Even then, the only result would be lower volume levels which you
should be able to compensate with the volume control.
As for the output impedances, they are 200 ohms and 60 ohms,
respectively. Once again I can't see these as being significant since
the Rin of the power amp stage is 100K or so.
- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.