MRT USB TERMINAL ONLY WORKS WITH 3.3V

[gps31]

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)

is it repairable? which parts to check?

[legija]

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.

[fzabkar]

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

[gps31]

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

[fzabkar]

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.

[gps31]

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?

[fzabkar]

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

[gps31]

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

can't understand. Can you spot those black things

[fzabkar]

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.

[gps31]

Marking

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

[fzabkar]

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

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

[fzabkar]

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

[fzabkar]

@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

[mrtlabinfo]

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)

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

[Amarbir[CDR-Labs]]

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)

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 .

[lcoughey]

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.