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MRT USB TERMINAL ONLY WORKS WITH 3.3V
http://forum.hddguru.com/viewtopic.php?f=28&t=41847
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Author:  gps31 [ November 1st, 2021, 3:21 ]
Post subject:  MRT USB TERMINAL ONLY WORKS WITH 3.3V

My MRT USB Terminal now works with only 3.3v supported HDD before this it works with 3.3v & 1.8v.

Now i can't work with 1.8v (Greenda, Rosewood etc)

Attachment:
MRT USB Terminal.jpg
MRT USB Terminal.jpg [ 1.23 MiB | Viewed 17195 times ]


is it repairable? which parts to check?

Author:  legija [ November 1st, 2021, 7:19 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

I presume that U2 is logic level translator, try to find out which one is it and provide I/O level power to corresponding pin. U3 and U4 could be regulators providing 3.3 and 1.8 as detected.

Author:  fzabkar [ November 1st, 2021, 14:58 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

CP2102 has a built-in 3.3V LDO regulator, so I expect that the external LDOs may be 1.8V and 2.5V.

Author:  gps31 [ November 2nd, 2021, 1:45 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

How to check and troubleshoot the problem? i don't have much knowledge in this

Author:  fzabkar [ November 2nd, 2021, 15:10 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

Connect Tx to Rx and then perform a loopback test using PuTTY, HyperTerminal, or some other communications software. I could be more specific, but all I see are black things.

Author:  gps31 [ November 4th, 2021, 2:26 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

It is working with ST3500418AS and 500DM002 etc

but not working with latest model HDD (ie. No Terminal OUTPUT) drivers changed but no luck

1.8v and 2.5v is not supported but some days before Adapter worked well.

how to repair this?

Author:  fzabkar [ November 5th, 2021, 13:31 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

I can't help you because all I see are black things.

Author:  gps31 [ November 7th, 2021, 2:11 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

fzabkar wrote:
I can't help you because all I see are black things.


can't understand. Can you spot those black things

Author:  fzabkar [ November 7th, 2021, 12:26 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

gps31 wrote:
fzabkar wrote:
I can't help you because all I see are black things.


can't understand. Can you spot those black things

U1, U2, U3, U4.

Author:  gps31 [ November 8th, 2021, 0:55 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

Marking

U1 : SILABS CP2102 DCL0XN 1643
U2 : LVC125A 266 124 SXD14 03D
U3 : VCZ
U4 : VCZ

Author:  fzabkar [ November 8th, 2021, 13:49 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

There don't appear to be any LDO regulators. Instead U3 and U4 appear to be Schmitt trigger inverters, and these perform the level translation. The RxD input appears to be cascaded through these two inverters before passing to U2 and then on to CP2102.

I would set up a loopback test with RxD connected to TxD, and then send a continuous stream of "U" characters (alternate 1s and 0s). Use a scope to monitor the signal transitions.


L74VHC1GT14, LESHAN RADIO COMPANY, Schmitt-Trigger Inverter/ CMOS Logic Level Shifter, marking VCx, SOT23-5:
https://www.alldatasheet.com/datasheet-pdf/pdf/280539/LRC/L74VHC1GT14.html

Quote:
The device input is compatible with TTL–type input thresholds and the output has a full 5 V CMOS level output swing. The input protection circuitry on this device allows overvoltage tolerance on the input, allowing the device to be used as a logic–level translator from 3.0 V CMOS logic to 5.0 V CMOS Logic or from 1.8 V CMOS logic to 3.0 V CMOS Logic while operating at the high–voltage power supply.


SN74LVC125A, Texas Instruments, Quadruple Bus Buffer Gate With 3-State Outputs, marking LVC125A:
https://www.ti.com/lit/ds/symlink/sn74lvc125a.pdf

CP2102, Silicon Labs, USB-TO-UART BRIDGE, QFN-28:
https://www.silabs.com/documents/public/data-sheets/CP2102-9.pdf

Author:  fzabkar [ November 8th, 2021, 14:52 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

MC74VHC1GT14, ON Semiconductor, Schmitt-Trigger Inverter / CMOS Logic Level Shifter, marking VCm, SOT23-5:
https://www.mouser.com/datasheet/2/308/mc74vhc1gt14-d-1193426.pdf

Author:  fzabkar [ November 9th, 2021, 15:44 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

@gps31, did you get anywhere with this?

You can create a file consisting of 100K repetitions of the letter "U" and then transmit it to your adapter's virtual COM port at 300bps (= 30 bytes per second). That should give you 55 minutes of troubleshooting time before you need to resend the file. Or you could create a 1MB file for 9 hours of troubleshooting.

Attachments:
1MB_U.7z [347 Bytes]
Downloaded 394 times

Author:  mrtlabinfo [ May 9th, 2022, 3:26 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

gps31 wrote:
My MRT USB Terminal now works with only 3.3v supported HDD before this it works with 3.3v & 1.8v.

Now i can't work with 1.8v (Greenda, Rosewood etc)

Attachment:
MRT USB Terminal.jpg


is it repairable? which parts to check?


You can refer to this link to have a look
http://us.mrtlab.com/tech/otherdisk/307.html

Author:  Amarbir[CDR-Labs] [ May 9th, 2022, 9:45 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

mrtlabinfo wrote:
gps31 wrote:
My MRT USB Terminal now works with only 3.3v supported HDD before this it works with 3.3v & 1.8v.

Now i can't work with 1.8v (Greenda, Rosewood etc)

Attachment:
MRT USB Terminal.jpg


is it repairable? which parts to check?


You can refer to this link to have a look
http://us.mrtlab.com/tech/otherdisk/307.html


Hey Listen ,
We are trying to solve a issue here and you are doing your stupid marketing ,Either solve his problem or stop participating in threads .

Author:  lcoughey [ May 9th, 2022, 12:40 ]
Post subject:  Re: MRT USB TERMINAL ONLY WORKS WITH 3.3V

Amarbir[CDR-Labs] wrote:
Hey Listen ,
We are trying to solve a issue here and you are doing your stupid marketing ,Either solve his problem or stop participating in threads .

Are they not solving the issue by having discontinued the old aterminal adapter in the OP with a new adapter wirh faster speeds and voltage settings?

What they failed to do is provide a link to easily order the newer adapter in ther post above or on the linked web page.

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