Please help Hioki 3334 AC/DC Power Hitester display blank - Page 1
Forum section: electronics / repair

author: Wahyueko
author_rank: Contributor
timestamp: January 08, 2023, 07:48:58 pm
content: Please helpI have a Hioki 3334 AC/DC power hitester, an error occurred, on the previous display it said Error 4, and now there is no display on display.After I dismantled it, it turned out that there was no data signal on the MCU and FPGA either, I checked the clock, and there was a 19MHz signal according to the crystal. however, there is no data signal. only output voltage 3.3V.I have also tried removing the FPGA but the results remain the same on the MCU and there is also no data signal.Can the MCU be replaced immediately or are there other parts that need to be checked?MCU f2328vf25v H8s/2328Fpga XC3S200

author: Chris56000
author_rank: Frequent Contributor
timestamp: January 08, 2023, 09:27:29 pm
content: Hi!I'm afraid you might be out of luck with this one, as the MCU datasheet (Renesas just LOVE publishing things as thick as two hefty Yellow Pages –1302 pages!!), clearly indicates that both flash Memory and Code Protection is incorporated in this device – If Hioki make a firmware file separately available, you might be able to I.C.S.P. ("In–Circuit–System–Programming") it, providing you can get a flash utility (Renesas may offer this), but I fear you've got a very large and expensive doorstop if the MCU is defective!All I can suggest you try is to trace what's connected to the MCU address and data lines, and see if there's any RAM or other interface ICs you can disconnect or replace, otherwise you might have to get a new MCU, and if it doesn't come on, you're at the mercy of Hioki themselves!Chris Williams

author: Martin72
author_rank: Super Contributor
timestamp: January 08, 2023, 10:29:53 pm
content: QuoteGood luck...

author: Swake
author_rank: Frequent Contributor
timestamp: January 09, 2023, 01:31:51 pm
content: - Do the power supplies measure fine on a multimeter and look good on a scope?- Is there a reset circuit or voltage monitoring circuit?- Have you measured power on the power pins of the MCU?

author: Wahyueko
author_rank: Contributor
timestamp: January 09, 2023, 08:13:19 pm
content: Yes already measured. i have 1 normal like it. I have compared it to the normal one, all voltages are the same. but on the pin where there is a signal, data does not come out, but outputs a voltage of around 3.4V.

author: Wahyueko
author_rank: Contributor
timestamp: January 09, 2023, 08:53:17 pm
content: Thanks i will do it

author: Wahyueko
author_rank: Contributor
timestamp: January 09, 2023, 08:59:19 pm
content: the clock its very small signal about 454mVpp. frequency 19MHz , offset high 1.5V, I tried to replace the crystal, but the result is the same.

author: Swake
author_rank: Frequent Contributor
timestamp: January 11, 2023, 06:43:00 pm
content: I don't know what you measure exactly. Not that easy to measure a X-tal correctly. Could be the circuit is overloaded during measurement. Impedance matching, capacity of probe and bandwidth of scope and many more things can influence a lot. Also length of ground wire of the scope should be really very short.Can you compare with the working device?Because you have oscillation at the correct frequency I'm inclined to think the X-tal itself works.Is the X-tal in a circuit that contains some logic gates or a transistor to make pulses from the X-tal signal? You have to measure that output. Then find the input clock pin on the MCU and check again there what signal you have.