Fixed 2 channel no DCS

Sounds like the ACT244 Chip needs replace. Search ACT244 and several post will come up on these chips and how to replace them. It's a bit of a challenge.

the ACT 244 BUFFERS ic's are easily damaged with voltage transients that's why tvs diodes are installed on output of all 4 Tiu channels! As stated not easy to change and DON'T LIKE TRACK SHORTS OR DERAILMENTS!

74ACT244SC onsemi | Integrated Circuits (ICs) | DigiKey here are the buffers

Alan

If he changed the receiver chip without an issue, he shouldn't have any issue with the 72ACT244 chips.

If the 72ACT244 chips. went bad , why would dcs work on the three other channels with out any problems on those channels
does fixed 2 channel have its own DCS chip, if so what is the PCB ID number as in U number thanks guys

Fred

Each channel has one '244 driver.  For loss of DCS signal on one channel, replace the following components, type 74ACT244SC.

Var #1 - U340, Fix #1 - U341, Fix #2 - U440, Var #2 - U611

Thanks John I’ll let you know later how it worked I have those chips I believe

Hi John ,

I changed the 244 chip for fixed 2 channel, it worked for a little while perfectly.

I then checked the remaining channels, set the variables to fixed, and got engine not on track. I shut the power off then back on, and then it worked again. I did this several times on all of the channels , with the same intermittent results on all channels,  engine not on track, turn off the power ,and back on again then it works ok .

TUI powered by aux power .
Intermittent, I even removed and reseated the TIu RF BOARD THINKING THE PINS MAY HAVE CORROSION ON THEM ,IT  WORKED  ONE TIME AND THEN BECAME INTERMITTENT AGAIN. IS IT POSSIBLE the RF board went bad as well?

FRED

RF errors could be the transceiver, but ENGINE NOT ON TRACK isn't.  Not sure what is going on.

One thing that occasionally bites me, make SURE there is no other TIU around that might be powered.  Even connected just to USB from a computer can be enough to screw things up, don't ask me how I know that.  I have a TIU on my workbench, and of course, on the layout.  If I forget to disconnect and power down the bench TIU, odd things happen.

Up date ,

I went out to do a house call , came back ,put a different one on the track did a lash up ,low an behold all CHANNELS WORKED FINE EVEN IN LASH UP

go figure I will test again tomorrow morning

have a good night

Fred

Ghosts?

Ghosts! Indeed !

update :Tiu seems to be working fine , when I saw  “engine not on track” I made me rethink it could be the engine . The engine I was using was a subway lo v ps2 , my other subway is ps3 r33 . The lo v gave me problems at the club, “Eng not on track “Issues , during our train club open house show , the ps3 subway never gave me a bit of trouble . I suspect The lo v has a loose connection on the pcb , that’s a repair for another time . My r 33 subway is now my test engine . I rechecked both engines in lash up and found lo v had the problem . TIu worked fine .

I have more TIUs to be repaired that are mine ,and customers , so I  will have to wait till I can get to mine. One of them when I connect it to power through aux plug blinks 8 times. I read in Barry’s book to do a software reinstall to see if that corrects the problem , that one is on the bottom of the list . Lol

Engines and conversions come  first !
soldering 244 chips was easy for me , what was a challenge was a ps3 steam pcb audio chip where all the connections are on the bottom of the chip , I used hot air and a tripling optical lens to see the chip . **** small , thank God my eyes are still good ! I had to do 3 of those chips already , all good on the first shot . Those chip soldering how-to videos paid off .  Now on to led conversions. Thanks again for all your help

Fred

Up date the one TIu that did t work properly had a loose RF board some foam in place stopped that from happening again all good .

Fred