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QSF-430L-3U False heater power failure message

juan thomas

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Hi all, have a QSF430 that is displaying a false "heater power failure message".

We are in fact getting heat to all chem tanks and dryer.

Machine is otherwise functioning normally.

Ran through all checks in service manual, fuses + relays check out ok, but readings on plug J/P27 only comes in at around 100v on pins 1-9 and 0v on pins 3-9 when they both should come in at 200-250v.  Noritsu phone tech says it's either the cpu board or relay board....$30 please....gee thanks.  Just trying to figure out which one to start with.  Any ideas?   Thanks.

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Not got my old paper manuals for the 430 anymore but remember a board mounted relay around the middle of the relay PCB that monitors the mains in and what Hertz is running, the contacts get pitted and it will give heater power failure. I am sure an adult will be along with the drawings and tell you what the relay number is, I think you can prise the top of the relay and clean the contacts but its been a few years since I worked on one.

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The heaters are supplied voltage by relay X-11 on the Relay PCB but first,  to energise this it is latched by X-6 which in turn operates via  the  tank/heater thermal fuses encapsulated inside the float  switches. The are all "daisy-chained"  together, so if one blows then in theory none will heat up.

You say that all is functioning as it should aside from the error  message which points more to the  voltage sensing circuit. When X-11 operates it powers all four heaters as well as a feedback loop to the sensor circuit. This  comprises a couple of (put simply) optocoupled varistors on the input side of Q4. If one or both fail to see the voltage then Q4 will change state and handshake the CPU with an error condition.

Take a look at the next post with the circuit digram.

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  • 3 months later...

Hi Team I am having this same problem but not getting any heating at all I have changed the fuses and even the relay but to no avail

Shes a very old and tired machine and many thing dont work I have taken out alot of ssrs and heaters that arent vitally important is there

someway of bypassing a faulty temp unit or something like it to get it opoerational again

Any thoughts greatly appreciated..

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Looking at the above diagram, you should have 200-240VAC (voltage dependent on the country you're in) between terminal T1 & T2.

Then there should be the same voltage between pins 3 & 9 on J/P27.

If you have voltage on T1 & T2 but not on pins 3 & 9 on J/P27, check the relay X11 is operating and that the contacts are clean and not pitted etc.

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Thanks for your reply ,Must admit I,m not that great with schematics I have attached a picture of the board could you please point me in the direction of t1and t2

board No is j302681-02 so I think this makes it a 430 and not a 430l Its been a bloody long time since I bought it.

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You've steered us off an  a bit of a  tangent here mate. The photo above looks to be a 4100-L series  and not  the relay control PCB for a 430L-3U.  Can't quite read the part number, should be J303683, can you please confirm.  Wiring, PCB's  and layout  totally different.

Wiring diagrams for 4100L attached.

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Looks like the PCB has had a hard life, the remains of 2 burnt SSr at the bottom..

This PCB is responsible for some bad contacts and can be a fire risk, Japan now say it should be replaced at around 5 years.

We tend to think that PCB's last forever but they don't, especially when you have mechanical relays the contacts arc and burn over time

From my memory (getting sketchy on this model) its the small yellow relay (top left) that is in the detection circuit. It can be butcherd to open it but just try tapping it to see if you hear it kicking. I personally would replace it with another unit if you can find it, and re solder all SSRs as they get dry joints and start to arc.

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Definitely not a 430L series! It could even be a 450L (Not a 450L-2 or -3) They came with the QSS-1001V

Peel off the white sticker with the part number on it to reveal the Noritsu part number!

Take a wide angled picture of the whole machine then we can identify it more easily for you.

The 450L does around 50 films an hour. The 4100L-1 does around 100 films an hour and is a big long machine with lots of racks!

Looking at the state of that board the cause is probably burnt out tracks.

I agree with Magenta it would be much safer to get hold of another PCB, and check and re-solder the joints as required.

The problem is the relays are quite heavy, and with the vibration of the machine the solder joints crack then start to ark and eventually burn the board.

The newer V series also suffers from the same issue.

Maybe it's time to lay the old girl to rest and get a V50 to replace her, they are very cheap now, and you'll save on the electricity bill as well!

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The wiring diagram here should be the same as your machine.

We probably should look to the most logical assumption to diagnose what's going on here. My first suspicions would be one of the float switch units. Inside each one is a thermal fuse for the heater circuit, and a reed switch activated by the float  to confirm correct tank level.

Check the floats move freely on the stem. Over time these float swtiches are known to swell and fail through the ingress of chemistry into their body which can cause the float to bind on the shaft. For normal operation they should all be closed. The thermal fuse may have blown due to another fault not yet obvious. Again if there is no continuity to energise  relay X14 (on your machine) then no power will be applied to the heaters.

As described in the above posts, these two control circuits are "daisly chained", so if one link fails or goes open circuit then no power will be applied to the heaters, fail-safe protection.

Turn the power off, with a meter check whether you have continuity at F & H, lift one wire off first. likewise at JP23 remove the connector and measure across pins 1 & 2 looking back to the wiring harness. Whilst most of the control circuitry is 24 Volts, caution should be applied when measuring or checking wiring around this area with power applied as full line voltage will be present especially around the relays and on the Relay Control PCB.

When you turn the processor on, do the fans run?  Does all else seems OK except no heaters. No other indications of an underlying fault. Can you hear X14 clicking, look at it carefully, does it energise when you turn the power off and on. Might be pitted or dirty contacts here if it works.

Let us know how you go

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4100L with relay X14  heater control wiring. Not sure how many heaters your 42R has but should be identical to this configuration........

You might consider the advice of Dave-S and Magenta re putting the machine out to pasture. These relay boards do suffer from  mechanical fatigue causing all sorts of eroneous problems, sometimes hard to track down. If all checks out, we can't discount the CPU-PCB as the root cause because the heater circuit also gets a handshake (enable) from the CPU for the heaters  by relay X3  for Temperature Control Main.

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Thank you photocorp for your assistance turns out my machine is a 450 and not a 430 I have found a nice gentlemen not far from me with a 430l which is out of service

and I am able to take any parts I require what I dont know are the main boards the same or can be modified to suit my 450..

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Don't like your chances of being able use the boards from a 430. Part numbers are different,  wiring, PCB component layout, dispostion of relays and their  assignments not really compatible.

Within the same basic QSF model type there were variants for both Control and Relay PCB's. There were four versions of the 450 and three for the 430. Some parts interchangeable, some not.

You could maybe poach the relays and SSR's for future repairs.  If the 430 was in a functional condition not too long ago then it might be worth considering to resurrect it from the dead.

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