Are all LM4562NA created equal?


morseoneuk
 

Hi, After destroying my QCX20..  I was lucky to obtain another unpopulated board from Hans.
I had managed to salvage all the hardware from the damaged board, encoder, display, sockets, toroid's microswitches etc...
I had 99% of new caps, diodes, resistors and transistors etc   the only thing I had to source were  the lm4562na op-amps.
being over cautious this time I socketed all these devices. ( I know that there is a bit of a debate going on at the moment regarding this )
Any how, the build was completed , power on , display booted up just fine. audio heard in my speaker, all looked to be going fine.
dummy load attached, went to calibrate menu for alignment...   and nothing. zero displayed adjusting the capacitor made no difference at all.
switched to transmit and good power out 4.5 watts indicated on my meter.
I immediately suspected the sockets, so I re-seated all the devices, but no difference. all voltages to devices were good.
The op-amps are National semiconductors.. 
back to my scrap board..  de-soldered the amps and fitted them to the new board one at a time.. there was a noticeable improvement with each device changed..
  now working and able to  calibrate...   
What manufacturer are the original supplied op-amps...  is there a marked difference in suppliers products, or have I just got lucky by changing out all the amps?
Best Regards to the group
Scotty    Gi0bey




geoffrey pike
 

What happens if you put the old op-amps back in after being able to calibrate?
cheers
Geoff
GI0GDP

On Tuesday, 23 July 2019, 08:30:57 BST, morseoneuk via Groups.Io <morseoneuk@...> wrote:


Hi, After destroying my QCX20..  I was lucky to obtain another unpopulated board from Hans.
I had managed to salvage all the hardware from the damaged board, encoder, display, sockets, toroid's microswitches etc...
I had 99% of new caps, diodes, resistors and transistors etc   the only thing I had to source were  the lm4562na op-amps.
being over cautious this time I socketed all these devices. ( I know that there is a bit of a debate going on at the moment regarding this )
Any how, the build was completed , power on , display booted up just fine. audio heard in my speaker, all looked to be going fine.
dummy load attached, went to calibrate menu for alignment...   and nothing. zero displayed adjusting the capacitor made no difference at all.
switched to transmit and good power out 4.5 watts indicated on my meter.
I immediately suspected the sockets, so I re-seated all the devices, but no difference. all voltages to devices were good.
The op-amps are National semiconductors.. 
back to my scrap board..  de-soldered the amps and fitted them to the new board one at a time.. there was a noticeable improvement with each device changed..
  now working and able to  calibrate...   
What manufacturer are the original supplied op-amps...  is there a marked difference in suppliers products, or have I just got lucky by changing out all the amps?
Best Regards to the group
Scotty    Gi0bey




Hans Summers
 

Hi Geoff 

My understanding of what Scotty is saying is that the new LM4562 he purchased to populate his new PCB didn't work. So he desoldered the old ones (original QRP Labs ones) and they worked. 

I can't think why that would be, unless it was something else unrelated which accidentally got fixed, along the way.

73 Hans G0UPL 


On Tue, Jul 23, 2019, 20:49 geoffrey pike via Groups.Io <gi0gdp=yahoo.co.uk@groups.io> wrote:
What happens if you put the old op-amps back in after being able to calibrate?
cheers
Geoff
GI0GDP

On Tuesday, 23 July 2019, 08:30:57 BST, morseoneuk via Groups.Io <morseoneuk=yahoo.com@groups.io> wrote:


Hi, After destroying my QCX20..  I was lucky to obtain another unpopulated board from Hans.
I had managed to salvage all the hardware from the damaged board, encoder, display, sockets, toroid's microswitches etc...
I had 99% of new caps, diodes, resistors and transistors etc   the only thing I had to source were  the lm4562na op-amps.
being over cautious this time I socketed all these devices. ( I know that there is a bit of a debate going on at the moment regarding this )
Any how, the build was completed , power on , display booted up just fine. audio heard in my speaker, all looked to be going fine.
dummy load attached, went to calibrate menu for alignment...   and nothing. zero displayed adjusting the capacitor made no difference at all.
switched to transmit and good power out 4.5 watts indicated on my meter.
I immediately suspected the sockets, so I re-seated all the devices, but no difference. all voltages to devices were good.
The op-amps are National semiconductors.. 
back to my scrap board..  de-soldered the amps and fitted them to the new board one at a time.. there was a noticeable improvement with each device changed..
  now working and able to  calibrate...   
What manufacturer are the original supplied op-amps...  is there a marked difference in suppliers products, or have I just got lucky by changing out all the amps?
Best Regards to the group
Scotty    Gi0bey




morseoneuk
 

Thanks for the reply..
I sat for a while tonight and did just that,,,   swapped ic5 back to my new chip. and again  could not peak BPF although I could hear a very weak tone .. swapped again for my originally salvaged chip and all became good again...    maybe I just have a bad batch of lm4562  ..  
I have ordered a couple of lm4562 from RS components.... will see if the texas instruments chip is any better...
Cheers  Scotty

On Tuesday, 23 July 2019, 20:51:14 BST, Hans Summers <hans.summers@...> wrote:


Hi Geoff 

My understanding of what Scotty is saying is that the new LM4562 he purchased to populate his new PCB didn't work. So he desoldered the old ones (original QRP Labs ones) and they worked. 

I can't think why that would be, unless it was something else unrelated which accidentally got fixed, along the way.

73 Hans G0UPL 


On Tue, Jul 23, 2019, 20:49 geoffrey pike via Groups.Io <gi0gdp=yahoo.co.uk@groups.io> wrote:
What happens if you put the old op-amps back in after being able to calibrate?
cheers
Geoff
GI0GDP

On Tuesday, 23 July 2019, 08:30:57 BST, morseoneuk via Groups.Io <morseoneuk=yahoo.com@groups.io> wrote:


Hi, After destroying my QCX20..  I was lucky to obtain another unpopulated board from Hans.
I had managed to salvage all the hardware from the damaged board, encoder, display, sockets, toroid's microswitches etc...
I had 99% of new caps, diodes, resistors and transistors etc   the only thing I had to source were  the lm4562na op-amps.
being over cautious this time I socketed all these devices. ( I know that there is a bit of a debate going on at the moment regarding this )
Any how, the build was completed , power on , display booted up just fine. audio heard in my speaker, all looked to be going fine.
dummy load attached, went to calibrate menu for alignment...   and nothing. zero displayed adjusting the capacitor made no difference at all.
switched to transmit and good power out 4.5 watts indicated on my meter.
I immediately suspected the sockets, so I re-seated all the devices, but no difference. all voltages to devices were good.
The op-amps are National semiconductors.. 
back to my scrap board..  de-soldered the amps and fitted them to the new board one at a time.. there was a noticeable improvement with each device changed..
  now working and able to  calibrate...   
What manufacturer are the original supplied op-amps...  is there a marked difference in suppliers products, or have I just got lucky by changing out all the amps?
Best Regards to the group
Scotty    Gi0bey




Jim W7EED
 

FYI, T.I. bought National Semiconductor so current T.I. parts are the same as the older National parts, just different marking.
--
73,
Jim W7EED


morseoneuk
 

Texas Instruments chips arrived and yes Jim, same logo on them as the National Semiconductor ones.
.  The difference is that the new T.I. ones work well....   It must have been a bad batch.... or Chinese clones   :-)
any how all sorted now...
best regards to the group....Scotty