Osram Quicktronic QT 1×58 Modern Dimmable Fluorescent Light Repair
This short repair is about an Osram Quicktronic QT 1×58 modern dimmable Fluorescent light (58Watt upto 70Watt tubes). A friend of a friend has a Turkey Farm where they have collected a lot of these defect electronic quicktronic devices. And over time a couple of them end up at my place for investigation on why they no longer do work.
Most of them in the past were corroded by moisture caused by regular cleaning sessions when water got into the light controller circuits. And others in the past stopped working simply because the 10uF 460V capacitors had broken legs or broken cilinders. The latter were easily fixed by replacing the e-caps, but in the newer board versions the now new 500V 10uF capacitors no longer are causing any problems.
Previous photo shows the 230V transformer L1 that is fed by the 230V AC input voltage on connector pins 1 and 2. And next photos show why this device no longer was working.
On this board there were 2 special safety fuses integrated on the pcb solder side surface in the 230V input tracks. So not the usual glass type or plastic type of fuses anymore! And one of the input line printed fuses had completely vaporized. As also was indicated by the spot that was left on the plastic inside foil after the special print fuse melted which is shown on another photo. The diode bridge rectifier was conducting in one direction on both its ~AC pins. My DCA 75 detected a single diode there which clearly was wrong. The 230VAC transformer tested okay!
The 230V AC transformer clearly was not the reason why one of the pcb fuses blew. As above photo obviously proves. It indeed was the diode bridge right after the transformer that caused the overcurrent. The 3 marking on the pcb solder side on above photo on the right is the position where the 1…10V transformer is placed that regulates the Dim function. I could detect a good output function on this transformer with my Blue Ring tester but the 2 closer input pins did not show any measuring.
After I replaced the diode bridge with a good one from another Osram quicktronic pcb, I tested the 230V input and measured if the 10uF 500V e-cap did charge. It showed about a perfect 324 DC voltage.
I also checked the other transformers and they all tested fine with the Blue Ring tester. And I also tested a couple of the semiconductor N-channel Mosfets with my Peak Atlas DCA 75 Pro which only could be done after removing them from the board. As testing in-circuit was not possible and only resulted in a “No object detected” message.
In the past most of the replaced 10uF 460V capacitor defects worked afterwards. And since I do not have the FH21W 85CM tubes nor the external dimmer circuit I hope that also this repair will work.
Next photo shows another QT 1×58 board that has a slightly corroded Dim circuit on the right from the previous mentioned Dim transformer. But strangely on this board the transformer is marked position 6. After I cleaned it with an old toothbrush and some gasoline (Dutch: wasbenzine) it showed no signs of bad tracks or bad components.
Here follows the datasheet of the defect diode bridge a single phase 1A 700V RMS rectifier:
Repairing products like these without any service manual or circuit from the manufacturer is never easy. So I hope this repair at least contributes in fixing some of the 230V AC input problems on the
Quicktronic Osram 1×58 FH lamp controllers. And especially about the uncommon safety fuses that are used in this product.
Albert van Bemmelen, Weert, The Netherlands.
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Note: You can read his previous repair article in the below link:
https://jestineyong.com/warning-for-bad-blu-ray-discs/
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Henrique J. G. Ulbrich
November 5, 2019 at 12:02 am
Very good job, Albert. Thanks for sharing. Just a question: how did you end up that a 0.1 mm thick wire would be the right choice in this case? Did you have a previous idea of the consumption of this equipment?
Albert van Bemmelen
November 5, 2019 at 4:05 pm
Good question Henrique. But that is just the thinnest wire I have of which I know it survived the repaired connection without being unsafe if another short circuit should occur. And also because the second original printed fuse in the 230V AC input line on that board is still intact and safely working.
Robert Calk Jr.
November 5, 2019 at 12:25 pm
Good job, Albert!
Waleed Rishmawi
November 5, 2019 at 2:58 pm
a job well done my friend. I had a similar situation with these kind of lights in a chicken farm but the customer wanted me to do the repair in the farm and I could not due to the fact it was too smelly and I could not handle the smell. the way they were wired up the customer was not happy of take them apart then putting back there after the repair.
have a blessed day
Albert van Bemmelen
November 5, 2019 at 9:02 pm
Luckily I didn't smell anything Waleed. But you have a point. It is always best to be careful when opening these things because of unwanted insects that could invade our homes afterwards. I heard of Dutch people who already have bed bugs in their sleeping rooms after they went to a winter vacation in a hotel in the Czech Republic two years ago. And the Dutch Pest control firm Rentokill was not yet able to exterminate the plague that mostly pestered the children when they were sleeping. Which is quite unexpected why it was on Dutch TV yesterday. Have a blessed day too my friend!
Parasuraman S
November 5, 2019 at 5:39 pm
Very in-depth service experience is shared by you, for which we all should be thankful always. Because sharing a knowledge that too a practical experience is very uncommon, especially with professionals who live out of its income. That's why we can find a few 'dislikes' on almost all our articles. I have only sympathy for such. Good job there, Albert!
Albert van Bemmelen
November 5, 2019 at 9:29 pm
I like it the way you said it dear Parasuraman! The dislikes often easily could have come from companies or sellers that disapprove the negative outcome the article has on their selling figures. Which doesn't really matter as long as our articles do help fixing most defects in our expensive consumer electronics. Benefiting sellers who care to listen to improve their products.
JOHAN FERNANDEZ
November 5, 2019 at 9:38 pm
Albert van Bemmelen, Weert, The Netherlands ESTIMATED FRIEND GUSTO IN SALUDARTE IT IS IMPORTANT IN ORDER TO MULTIPLY THE KNOWLEDGE IN LATIN AMERICA, THE TRANSLATION IN SPANISH OF ITS TEXTS IN ORDER TO ACHIEVE GREATER GOALS OF COMMERCIALIZATION I HOPE THAT MY HUMBLE SUGGESTION TAKES IT IN A DOMINICAN HOUSE IN LATIN AMERICA IMPORTANT THAT YOUR WEB PAGE HAS THE MULTI LANGUAGE OPTION AS ALIBABA OR AMAZON
Yogesh Panchal
November 9, 2019 at 11:52 pm
Good Job!Albert.