4 replies to this topic

[casandra9]

I ordered 5 TLC5940 from China, yes stupid me

It seams all 5 are garbage. I did solder a second Mainboard Expansion Board just to root out any mistakes I might have introduced on the first one. Here are my observations:

Test scenario:
- pin 21 (VDD) 3.27V
- pin 23 (BLANK) 3.27V
- IREF set to 10mA, resistor 4k against GND (checked!)
- no KLZ25 connected just PSU1 and PSU2, that means theres no control signal and since BLANK is HIGH the chip should be completely shut of

Observation:
- some outputs are ON and when I insert the four PC847 the chip becomes hot, so, obviously the current limitation does not work as expected
- the curious thing is, when I disconnect OK4 (PC847) the chip stays cold, so, it looks like one output port is drawing a lot of current, I found the one port and disconnected just that one and voila the chip stays cold (faulty output port is on PIN14 = OUT14) and this on all five chips!
- when I insert the KLZ25 and test outputs nothing changes, like I said, I tested this on two different Mainboards, even with Port14 disabled no other port is working, the output voltages do not change at all

IK that the chips have internal EEPROM for e.g. DOT control. Is it possible that this EEPROM overwrites external setup? How can you erase the internal EEPROM, the programming function is disabled while using the Pinscape Mainboard Extension Board. Or are the chips garbage?

[fhjui]

Hi,

yep, that was not a good idea to order TLCs from China-sellers. I had made the same experience some time ago and designed an adapter-pcb from smd-to-dil-package. In addition I had found a seller in GB, who sells working TLCs and was thankful for my hint of the existing fake-ICs. (https://www.ebay.de/itm/111056828725). But I think he only sends to europe.

ok,what can you do ?

• its very shure, that the TLCs ar fake, you can try to get the money back, the problem can be to send them back to china...rather expensive. Or if paid with paypal to get it back from paypal.
• without the mainboard (with the KLZ) and without the TLCs inserted, the outputs must be off.
• at first check the current consumption of the extension board. It should be round about 10mA.
• you can check the individual stages with help of my instructions of a simplified schematic with voltage values
  
• For testing of the ICs of the pinscape-brds, I have made a simple testboard with help of a breadboard
  I have uploaded the whole parts in a german pinball forum, because uploading of non-jpg files is not possible here on vpforums
  https://www.flipperm...latinen.245670/
  you can translate it with help of googe-translator
• I fear you need the smd2dil-adapter like mjr has mentioned https://www.vpforums...=14#entry500694
  the TLCs with smd-package are available at digkey or mouser
• the EEPROM is unimportant in this case
   

Edited by fhjui, 03 July 2022 - 11:02 PM.

[casandra9]

Ok, thank you! Danke! That confirms my observations. I am decent at soldering, so, this would have been one of my few mishaps. Es ärgert mich ein bisschen ist aber kein Beinbruch. Werde wohl oder übel den Adapter bauen. Was mich bis jetzt abgehalten hat sind Mousers shipping Mondpreise.
I have ordered those now: https://www.ebay.de/itm/185313315887. Gerade gesehen, wieder ein Laden in China, mal sehen
With my test circuit Ill test them as soon as the arrive and get the money back via PayPal if theyre faulty.
On the Aliexpress ones I missed the 15 days dispute period, a $20 learning. I contacted the vendor and told him, that Ill spread the word about his fakes.

Byers be aware of this Ali shop: https://www.aliexpre...0115945815.html, shenzhenYida Store, all fakes!

Edited by casandra9, 03 July 2022 - 11:45 PM.

[fhjui]

I hope that the parts you have ordered are ok.

If all goes bad, I can send you a few TLCs based on my smd2dil-adapter. I have some in spare and would sell them for a self cost price. Dont want to earn money with that.

One TLC would cost 8€+shipping, actual tested. But I have no experience with shipping costs in non-european countries.

[mrarcade]

I made adapters as well. Read about it here:
https://www.vpforums...c=34102&page=49