Firmware file for Thurlby PSU - Page 1
Forum section: electronics / repair

author: linker3000
author_rank: Contributor
timestamp: September 05, 2017, 06:26:28 pm
content: I have a 'revised' Thurlby 15V 4A PL154 power supply from the 1990s ('revised = the model with the blue case and push button display damping control). It's generally working fine, but has a glitchy display and I am looking for the firmware file for IC1, which is a PIC16C55XT-P - part 27250-2000 - just in case I need to replace it, or damage it while checking for dry joints. I have checked-in with Aim-TTi, who now own the brand and they are on the hunt and contacting 'old' engineers!Just posting here in case someone happens to have a copy from an earlier repair effort!?

author: macboy
author_rank: Super Contributor
timestamp: September 05, 2017, 11:09:51 pm
content: I have the firmware from the TSX1820/TSX3510 and from the PL320QMD. Both have a very similar front panel to yours. I have also disassembled and reverse engineered the TSX firmware and added funtionality (serial output of status plus other things).The firmware on your parallel-programmed PIC 16C55 can be read using a TL866 MiniPro programmer, and it can be burned directly onto an ICSP capable PIC 16F55/57/etc. My TSX's 16C55 was socketed, is yours?

author: JFJ
author_rank: Regular Contributor
timestamp: September 05, 2017, 11:38:19 pm
content: Quote from: linker3000 on September 05, 2017, 06:26:28 pmThat part number is common to Thurlby PL310, PL320 and PL330 revised issue power supplies. Hopefully, someone with any of those power supplies will be able to read the on-chip program memory for you (provided that the PIC's code protection bit isn't set).You may find this thread (about PL320 metering problems) helpful with your repair:http://www.vintage-radio.net/forum/showthread.php?t=50989

author: linker3000
author_rank: Contributor
timestamp: September 06, 2017, 07:07:36 am
content: Quote from: macboy on September 05, 2017, 11:09:51 pmInteresting! Yes the PIC is socketed and I have a TL866A. Did you write up your work?

author: linker3000
author_rank: Contributor
timestamp: September 06, 2017, 07:09:30 am
content: Quote from: JFJ on September 05, 2017, 11:38:19 pmThanks. I did find that forum thread. Fortunately I do have the service manual and schematics.

author: ElektroQuark
author_rank: Unknown
timestamp: September 06, 2017, 08:35:48 am
content: Quote from: macboy onYesterdayat 23:09:51I may ask, do you have the firmware for the TSX1820P?

author: macboy
author_rank: Super Contributor
timestamp: September 06, 2017, 12:54:59 pm
content: Quote from: linker3000 on September 06, 2017, 07:07:36 amI've always meant to do a big write up, and I've started but haven't found time or motivation to finish. Someday...Quote from: EdoNork on September 06, 2017, 08:35:48 amNo, just the ordinary one. I acquired it by simply reading the programmed PIC in my unit, since it didn't have the code protect enabled.The programmable TSX1820P is very different. In addition to its Z80 CPU+ROM+RAM used for GPIB and serial communication, it also has a PIC16C55 for the ADC and main display. That PIC16C55 does not share the same firmware as the regular one.

author: bd139
author_rank: Super Contributor
timestamp: September 06, 2017, 01:24:56 pm
content: I've got a PL310 here (same series but 30v 1a) and had glitchy display problems. Turned out to be a cap on the control board had gone bad and was pulling one of the rails low. That was about 5 years ago so I have no information on which one it was though. Worth checking them to start with.The latest problem with it are a few failed LED segments. Fun fun fun.The ones with the PICs in are quite reliable in general. The old brown ones are total shit though.

author: Assafl
author_rank: Frequent Contributor
timestamp: September 07, 2017, 10:50:01 am
content: Here ya go. PL330 V2 1.00.HTH.

author: Towger
author_rank: Super Contributor
timestamp: September 07, 2017, 07:37:40 pm
content: I have a PL154, gray case. But not the ability to read the PIC. I think the designer of these is a member here and posted a few years back.Also have brown 320, and sourced NOS replacement displays from eBay. If you take a display apart it consists of bare dies bonded to the PCB.

author: Assafl
author_rank: Frequent Contributor
timestamp: September 08, 2017, 02:47:21 pm
content: So it turns out that the 5V/7A board has different firmware than the main board I posted above.So I attached a zip file that has 3 different firmware files I downloaded from the PL330TP with a TL866 (in bin as well as Intel hex formats).Main Channel Firmware: PIC16C55XT-P V2 1.005-7V Channel Firmware: PIC16C55XT-P PL 5V V3 1.00GPIB Board PROM: MX27C256 PLP V1.10 GPIBHope this helps.-al

author: TheBay
author_rank: Unknown
timestamp: February 26, 2019, 10:27:28 pm
content: I've got a TSX3510, really interested in this firmware. How is the serial connected up?Also mine is a few years old now, does anyone else have high pitches high frequency smps audible noise from theirs when the device connected goes up and down in current or pulses. I find things like laptops connected to it or devices that use PWM etc it sounds annoying noisy. Steady or inductive loads it's fine with.

author: macboy
author_rank: Super Contributor
timestamp: February 27, 2019, 04:34:05 pm
content: Quote from: TheBay on February 26, 2019, 10:27:28 pmAre you referring to my modified firmware with serial output for the status? There are a few unused pins on the PIC, I simply chose one and implemented a bit-bang UART. The UART uses baud rate of 37400 (27 us period, so actually 37037 or < -1% error). This signalmustgo through an optocoupler (since the TSX supply is floating and can be at any potential WRT ground) before being sent to an external device like a computer. I used a common USB-UART dongle, since the USB will supply power for it and for the receiving end of the optocoupler.As for the noise, my TSX1820 units have never done that but maybe I haven't tried loads similar to yours. Try adding extra output capacitance, especially closer to the load rather than closer to the supply terminals. Also ensure that the sense terminals are securely connected to the output terminals on the terminal strip at the back of the supply. It should function safely without those links due to some resistors in the supply, but the hard link is best.

author: TheBay
author_rank: Unknown
timestamp: March 06, 2019, 05:41:27 pm
content: Quote from: macboy on February 27, 2019, 04:34:05 pmSorry I wasn't clear, I was referring to your firmware, an opto makes sense and use an abundance of them in work so will find something suitable.I don't recall seeing a PIC in mine, but its been a while since I've had the lid off.My sense terminals are all good, I did send this off to TTI a couple of years back for a service and they changed the 2 large filter caps, I might do a re-cap on it as I think mine is from around 1990!The noise comes from the switching transformer, I'll see if some fresh caps help, if not I might pot or conformally coat the transformer at work.

author: macboy
author_rank: Super Contributor
timestamp: March 07, 2019, 01:45:12 pm
content: Quote from: TheBay on March 06, 2019, 05:41:27 pmThe PIC is on the display board, and is used only for display; it plays no role in the operation of the actual power supply. The PIC's role is to set up an analog MUX to choose a signal to sample (Vset, Iset, Vout, Iout, OVPset), take samples from the 12-bit ADC, and convert the readings to decimal and display them on the multiplexed 8-digit 7-segment LED display. The original PIC16c55 had only 512 words of program memory and a couple dozen bytes of RAM, and operated at only 4 MHz (1 MIPS). It's amazing how much you can do, and how fast you can do it, when programming in assembly.QuoteCheck the filter caps C73 and/or C74. These are subject to very high ripple current which can contribute to failure.These power supplies normally operate at an ultrasonic switching frequency (80 kHz), as is typical for any SMPS, but at low output voltage and low (or variable) load, there is a possibility of pulse skipping. This can push the effective switching frequency down into the audible range.Do you have the service manual? It has excellent circuit descriptions and full schematics.

author: abel_li
author_rank: Newbie
timestamp: August 06, 2019, 08:52:22 am
content: Thank you, can you provide me with the firmware of TSX3510P?