using a TDA 8170 instead of a TDA 8177F?

B

b

Guest
these two vertical output ics seem almost identical, i think the 8170
needs a ref voltage on pin 1. can they be interchanged? if so, what
mods if any will be required.
cheers. B
 
b wrote:
these two vertical output ics seem almost identical, i think the 8170
needs a ref voltage on pin 1. can they be interchanged? if so, what
mods if any will be required.
cheers. B
Click to expand...
TDA8177 ICs are getting hard to find (discontinued).
Why not use it's smaller counterpart. The TDA8172 is a drop in
replacement that works for me. I have replaced 8177s with 8172s in
commercial 25" RGB monitors with no failures (2+ years) (Dotronix
DSV-25C video wall monitors). There should be a electrolytic capacitor
just off of the pins of this IC. It is usually a 100mfd with a voltage
rating between 35v and 50v. Replace this cap or you will be replacing
the IC again. (I use a 100mfd/63v which cuts down on failures).
No extra circuitry changes are needed if going from 8177s to 8172s. The
worst that can happen is the IC fails. I have used this IC in Toshiba
projection units also with no failures.
Good luck!
Dave
 
On 15 nov, 04:21, kvm <k...@neo.rr.com> wrote:
b wrote:
these two vertical output ics seem almost identical, i think the 8170
needs a ref voltage on pin 1. can they be interchanged? if so, what
mods if any will be required.
cheers. B

TDA8177 ICs are getting hard to find (discontinued).
Why not use it's smaller counterpart. The TDA8172 is a drop in
replacement that works for me. I have replaced 8177s with 8172s in
commercial 25" RGB monitors with no failures (2+ years) (Dotronix
DSV-25C video wall monitors). There should be a electrolytic capacitor
just off of the pins of this IC. It is usually a 100mfd with a voltage
rating between 35v and 50v. Replace this cap or you will be replacing
the IC again. (I use a 100mfd/63v which cuts down on failures).
No extra circuitry changes are needed if going from 8177s to 8172s. The
worst that can happen is the IC fails. I have used this IC in Toshiba
projection units also with no failures.
Good luck!
Dave
Click to expand...
Hi Dave
thanks a lot for the info. I actually picked up a couple of TDA8177
from my local supplier for about 2€ each. Have yet to test the set
extensively but I did replace the IC and cap you said, and two 1000uF
16v caps providing a +10v and -10v to the ic (used 35v 105ş types).

coincidentally I now have another set to fix, with a similar fault,
only it uses a TDA8178S - do you think the TDA8172 would work there?
the TDA 8178S is more expensive, at least in my local store. Ben
 
b wrote:
On 15 nov, 04:21, kvm <k...@neo.rr.com> wrote:
b wrote:
these two vertical output ics seem almost identical, i think the 8170
needs a ref voltage on pin 1. can they be interchanged? if so, what
mods if any will be required.
cheers. B
TDA8177 ICs are getting hard to find (discontinued).
Why not use it's smaller counterpart. The TDA8172 is a drop in
replacement that works for me. I have replaced 8177s with 8172s in
commercial 25" RGB monitors with no failures (2+ years) (Dotronix
DSV-25C video wall monitors). There should be a electrolytic capacitor
just off of the pins of this IC. It is usually a 100mfd with a voltage
rating between 35v and 50v. Replace this cap or you will be replacing
the IC again. (I use a 100mfd/63v which cuts down on failures).
No extra circuitry changes are needed if going from 8177s to 8172s. The
worst that can happen is the IC fails. I have used this IC in Toshiba
projection units also with no failures.
Good luck!
Dave

Hi Dave
thanks a lot for the info. I actually picked up a couple of TDA8177
from my local supplier for about 2€ each. Have yet to test the set
extensively but I did replace the IC and cap you said, and two 1000uF
16v caps providing a +10v and -10v to the ic (used 35v 105ş types).

coincidentally I now have another set to fix, with a similar fault,
only it uses a TDA8178S - do you think the TDA8172 would work there?
the TDA 8178S is more expensive, at least in my local store. Ben
Click to expand...
B,,
You might want to do a google search of TDA8170, 8172, 8177, 8178.
search as "TDA8172 pda" etc. You will find that the TDA8178 has a much
higher working voltage than TDA8170 and TDA8172 (90V) but lower current
handling (2A). There is a wealth of information available on the "net".
I think I'd spend the extra "pounds" and get the right IC as the working
voltage in the circuit would probably kill a lower voltage rated one.

Lots of great info on the net... Just remember to replace the "pump-up"
capacitor (100mfd/63v) as this is usually what causes the death of
these ICs.

Lots of luck!
Dave
 
On 16 nov, 16:50, kvm <k...@neo.rr.com> wrote:
b wrote:
On 15 nov, 04:21, kvm <k...@neo.rr.com> wrote:
b wrote:
these two vertical output ics seem almost identical, i think the 8170
needs a ref voltage on pin 1. can they be interchanged? if so, what
mods if any will be required.
cheers. B
TDA8177 ICs are getting hard to find (discontinued).
Why not use it's smaller counterpart. The TDA8172 is a drop in
replacement that works for me. I have replaced 8177s with 8172s in
commercial 25" RGB monitors with no failures (2+ years) (Dotronix
DSV-25C video wall monitors). There should be a electrolytic capacitor
just off of the pins of this IC. It is usually a 100mfd with a voltage
rating between 35v and 50v. Replace this cap or you will be replacing
the IC again. (I use a 100mfd/63v which cuts down on failures).
No extra circuitry changes are needed if going from 8177s to 8172s. The
worst that can happen is the IC fails. I have used this IC in Toshiba
projection units also with no failures.
Good luck!
Dave

Hi Dave
thanks a lot for the info. I actually picked up a couple of TDA8177
from my local supplier for about 2€ each. Have yet to test the set
extensively but I did replace the IC and cap you said, and two 1000uF
16v caps providing a +10v and -10v to the ic (used 35v 105ş types).

coincidentally I now have another set to fix, with a similar fault,
only it uses a TDA8178S - do you think the TDA8172 would work there?
the TDA 8178S is more expensive, at least in my local store. Ben

B,,
You might want to do a google search of TDA8170, 8172, 8177, 8178.
search as "TDA8172 pda" etc. You will find that the TDA8178 has a much
higher working voltage than TDA8170 and TDA8172 (90V) but lower current
handling (2A). There is a wealth of information available on the "net".
I think I'd spend the extra "pounds" and get the right IC as the working
voltage in the circuit would probably kill a lower voltage rated one.

Lots of great info on the net... Just remember to replace the "pump-up"
capacitor (100mfd/63v) as this is usually what causes the death of
these ICs.

Lots of luck!
Dave
Click to expand...
thanks again Dave. I have got the datasheets now. and will follow it
up.
I just checked the set in which I changed the TDA 8177F, the pumpup
cap would appear to be 33uF. I suspect a slightly higher value may
have been wise for reliability, who knows. reminds me of the vestel
11AK30 chassis line drive decoupler which is 10uF and many techs I
have spoken to replace it with a 47uF, since things run cooler that
way.
-B
 
b wrote:
On 16 nov, 16:50, kvm <k...@neo.rr.com> wrote:
b wrote:
On 15 nov, 04:21, kvm <k...@neo.rr.com> wrote:
b wrote:
these two vertical output ics seem almost identical, i think the 8170
needs a ref voltage on pin 1. can they be interchanged? if so, what
mods if any will be required.
cheers. B
TDA8177 ICs are getting hard to find (discontinued).
Why not use it's smaller counterpart. The TDA8172 is a drop in
replacement that works for me. I have replaced 8177s with 8172s in
commercial 25" RGB monitors with no failures (2+ years) (Dotronix
DSV-25C video wall monitors). There should be a electrolytic capacitor
just off of the pins of this IC. It is usually a 100mfd with a voltage
rating between 35v and 50v. Replace this cap or you will be replacing
the IC again. (I use a 100mfd/63v which cuts down on failures).
No extra circuitry changes are needed if going from 8177s to 8172s. The
worst that can happen is the IC fails. I have used this IC in Toshiba
projection units also with no failures.
Good luck!
Dave
Hi Dave
thanks a lot for the info. I actually picked up a couple of TDA8177
from my local supplier for about 2€ each. Have yet to test the set
extensively but I did replace the IC and cap you said, and two 1000uF
16v caps providing a +10v and -10v to the ic (used 35v 105ş types).
coincidentally I now have another set to fix, with a similar fault,
only it uses a TDA8178S - do you think the TDA8172 would work there?
the TDA 8178S is more expensive, at least in my local store. Ben
B,,
You might want to do a google search of TDA8170, 8172, 8177, 8178.
search as "TDA8172 pda" etc. You will find that the TDA8178 has a much
higher working voltage than TDA8170 and TDA8172 (90V) but lower current
handling (2A). There is a wealth of information available on the "net".
I think I'd spend the extra "pounds" and get the right IC as the working
voltage in the circuit would probably kill a lower voltage rated one.

Lots of great info on the net... Just remember to replace the "pump-up"
capacitor (100mfd/63v) as this is usually what causes the death of
these ICs.

Lots of luck!
Dave

thanks again Dave. I have got the datasheets now. and will follow it
up.
I just checked the set in which I changed the TDA 8177F, the pumpup
cap would appear to be 33uF. I suspect a slightly higher value may
have been wise for reliability, who knows. reminds me of the vestel
11AK30 chassis line drive decoupler which is 10uF and many techs I
have spoken to replace it with a 47uF, since things run cooler that
way.
-B
The difference in values may have to do with you being on the other side
Click to expand...
of the pond. Our (USA) scanning frequencies are 60hz vertical and
15575hz horz.
I believe your vertical scan rate matches your AC line (mains) frequency
of 50hz (at least for analog TV). Check the pump-up caps in a few TVs
as this may be the case.
I'd be curious to see if they are different.
Dave.
 
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