TNY266PN-failures
Gentlemen,
a swiss company, for which I'm working as a technical consultant, bought and sold over the last 4 years lot's of low power modules imported from China. In the near past, more and more TNY266PN Tiny Switch-II components fail. Nobody is able to find out the reason for those defect components. The modul is powered from a 90Vac to 264Vac 50Hz line and converts the input AC-voltage to an isolated DC-output of 3,3V at 1,25Amps as maximum load.
The failures are mostly related to TNY266PN - defects and, probably as a consequence, the input fuse, which is a slow blow 1,5Amp type, connected in series to the mains.
A conversation between the supplier, the distributor and the customer, did not give us any indication for reasons, which may have caused the trouble.
The customer promissed it's application is working within the specifications of the module's datasheet. Overvoltages at the input could be excluded as well as excessive overtemperatur operations.
On the other hand, the supplier is focussing on these two parameters, namely input overvoltage and operating temperature.
As mentionend earlier, the failures occured only in the near past, the last batsches of delivery. So, with excessive voltage and
temperature operation, also older units fronm earlier deliveries should have failed, but did'nt.
My questions:
1. TNY266PN is provided with an internal temperature protection ! Can it fail at all at overtemperature conditions ?
2. Did you change your production line in a way, that any component parameters are more critical today as they were in the
past. For example, one of the failed TNY266PN components is marked with "M543" and "36621E". Does this information
indicate any date code or production code / batch ?
3. Is it possible for you to test defective components in order to find out the reason for the failure ? (temperature, voltage,
current etc....?)
4. Is it possible to destroy the component, if the regulation loop is unstable ?
Unfortunately, the supplier is not willing to send us the complete circuit diagram, so I can only attach part of the circuit diagram I got.
Thank you very much for your detailed response.
Best regards
Dipl.Ing.Udo Huhn-Rohrbacher
Albert-Kratz-Str.1
D-75180 Pforzheim
phone: +497231-352339
fax: +497231-140338
mobile: +491523-3612096
E-mail: u.huhn.rohrbacher@googlemail.com
Comments
Hi PI,
I'm an EE for a Slot Machine company. One of the slot machines uses ARAS EVP-3005-00 power supply. The most common problem on this power supply is TNY266. I don't think the problem is TNY266, since the power supplies fails after 4-5 years of work. Nothing last for ever. Well, for sure some engineering reviews on this power supply can make it work for 10-20 years with out stop, but semiconductors' money flow stops.
Nevertheless, can I use TOP244 instead TNY266 on this power supply?.
Note: I don't have diagrams for the power supply.
Thank you
Eng Apache
TNY266 is a very different part than TOP244.
You need to redesign your power supply.
we use these a lot over past 7yrs- modules supplied by a vendor. but failures have not been due to inputs. most were due to output cap failure which started the process. This itself may be due to not totally thorough transformer design. If you use PIExprt tool you will never get that small a core. Indeed. when I tried to replace by my own design from PIExprt, my core from the design came out 4 times bigger!
If this is the case, then the input failure will be related to eventual device failure(s).
Hope this helps.
The TNY266 are very reliable parts. There are millions of parts in the field and up to now there is not failure due to the parts.
Before I reply your questions, would you like I take a look to your design? Usually is the standard procedure that here in the PI forum, a PI engineer (me) review the design to see if we can detect something suspicious.
If so, please attach your schematic picture, transformer design document and pcb layout picture.
PI-Worf