30 Mar 2015

Protek 608 multimeter overview

Protek 608 multimeter

The Protek 608 is a 5000 count digital multimeter made by Hung Chang, who have since changed their name to GS Instruments. I’ve owned one of these since about 2009. This multimeter is now discontinued and no longer available new, although they occasionally show up on the second-hand market from forums and eBay. This DMM was also rebadged and sold as the Voltcraft VC 608.

I’ve found it be be an excellent meter and was my go-to until I purchased a Fluke 116 a few years later. The Protek 608 still has many advantages over the Fluke 116, such as dual display and RS-485 data output. You may have seen it briefly in my transistor / component tester review video. I now predominantly use it as a data logging meter using software I’ve developed. The original probes broke on me, so I replaced them with some parrot clips on silicon leads which suits data logging well (clip the leads on, and leave it running).

Protek 608 with accessories
Here’s my Protek 608 with it’s carry bag, parrot leads (not original), thermocouple and adapter, RS-232 cable, and RS-232 to USB converter. I also have the original manual (not pictured).

The down-side to this meter is that it’s power hungry and will drain it’s 9V battery in about a day of constantly being on. Using an expensive lithium battery will run it for a few days, but it’s still quite limiting of long-term monitoring is required. I’m planning to modify my multimeter at some stage to allow for an external power supply to be used, but that in itself is troublesome (isolation and loss of rating, noise and interference, portability).

Protek 608 manual

I scanned in the original manual into a PDF (Download link). This is a more convenient referencing on my PC when developing software for the multimeter.

Protek 608 manual cover
Click here to download the manual

Plans for the future

Why not use the original software? Well after finally tracking it down I found 2 versions, one for Windows 3.x, 95, and 98, the other for Windows NT and XP. I’m running Windows 8.1 on my work laptop and when I try to run the installer I get this error message:

Protek 608 software installation error

The original software is clearly obsolete now. Besides, I’d also like to option to use Linux and customise the functionality. So I’ve decided to ‘roll my own’ and develop a software solution in Java for cross-platform compatibility.

Keep a look out for future posts that detail this software development, and how I’ve use it in the field. Once I have a stable version I’ll make the source code available via a git repository.

I also plan to post in future about my external power source modifications, and I have some ideas to develop a Wi-Fi or Bluetooth module. So if you’re interested, watch out for that too! 馃檪

About the Author:

Hardware and software engineer with experience in product development and building automation. Director at Cabot Technologies and Product Manager at NEX Data Management Systems.


  1. […] This is following on from my previous post introducing the Protek 608 multimeter and my software project. […]

  2. […] up the original Protek 608 software on an old Dell Inspiron 8100 I found stowed at the office. My previous attempts to run this software failed on Windows 8 and 10, and there’s very little information about […]

  3. Buddhika Ruwan Jayasooriya

    I am Buddhika from Sri Lanka. I am using uour Protek 506 Multimeter I want to buy Protek608.Please can you send me prices including shipping chargers.

    • Hi Buddhika, I’m not a shop and don’t have any for sale. They don’t make the Protek 608 any more, so your best bet is to look for a used one on electronics forums and eBay. Good luck!

  4. Jack Martin

    I use the old software in windows 7 by instaling in xp service pack 3 campabitle mode works in rs232 com port on the computor
    but will not work with the usb to rs232 converter what serial to USB converter do you use

  5. hakan seray 艧ibik

    hello I found protek 608.but the positive and negative feed ends are broken.I can not find the 9v feeders on the card.please help me. my e-mail [redacted]

  6. Jose Luis C贸rdoba

    Hola Amigo yo compre uno usado que lo habia descalibrado y te pregunto si existe alguna manera de calibracion por soft o recuperar los datos de calibracion anteriores ya que llevarlo a calibrar es mas caro que el aparato en si. Gracias saludos drsde Argentina.

    • Hola, perd贸n por la respuesta tard铆a.
      No he calibrado este medidor antes, pero hay instrucciones en el manual. Puede descargar el PDF de arriba – P谩gina 23, secci贸n 6-4.
      隆Espero que ayude! [Google translated from English]

  7. c50K1

    Hi Darian. I have 3pcs Protek 608 (2 pcs working well) 1pc was burnt, i bought it for reverse engineering project (sch
    will complete soon). I would like to read protek 608 KS57C2016 MCU. Furthermore, i have legacy protek 4000 too which is an benchtop type of protek 608 and i discovered Samsung MCU is S3P72P9 (OTP) is the difference. https://www.gsi-protek.com/4000 dmm is new version without Conductance and low voltage resistance measurement function. I think, in-circuit measurement function (open voltage 0.25V, very low current) very usefull for leakage mosfets, other semicunductors or resistors measure. I know, Yokogawa TY720 is an alternate but missing conductance function. Nonetheless, TY720 more acurate based on specification. I would like to stay with Protek 608 and protek 4000. Could you give help MCU reading? By the way, i found TsDMMViewer which is working under win7, it is support Protek 608 and Protek 506 too. You can download free from Japan site (need google translator to navigation) http://www.ts-software-jp.net/products/tsdmmview.html Legacy Protek 4000 is not supported because MCU is different than Protek 608. Unfortunatelly, i cannot use java source but great respect for your solution. Thank you in advance Master.

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