a upc1237 replacement board
That is exactly what I will do if the parts at the shop will fail.
I would use the circuits from Rod Elliot's project here as inspiration.
No luck with the C1237HA, it was money sent down the drain.
In my application, the Vcc is 20V, and all four pins no. 4,6,7,8 are at the same voltage: 20V.
It's just like I didn't solder the chip on the board, and I've triple checked everything.
I will try an original uPC1237 from an Akai amplifier just to verify if the circuit is allright. If it works, I'm going to start designing the replacement board for this chip.
In my application, the Vcc is 20V, and all four pins no. 4,6,7,8 are at the same voltage: 20V.
It's just like I didn't solder the chip on the board, and I've triple checked everything.
I will try an original uPC1237 from an Akai amplifier just to verify if the circuit is allright. If it works, I'm going to start designing the replacement board for this chip.
NAD has designed a small board to replace the uPC1237. See this thread for details: http://www.diyaudio.com/forums/solid-state/217282-nad-c315bee-help-repair-4.html
I've NAD C352 amp(Manufactured -Oct 2004) & it uses UPC1237 . It uses standard value passives as mentioned in UPC datasheet.
Yeah we poor DIYers are sitting ducks for these counterfeiters. Keep us posted about your results with the original uPC1237 from Akai.
Excuse my poor English
, but I've written about it a couple of posts above. It works fine with the good old NEC uPC1237 from the Akai.I've tried to crack open the counterfeited chip, hoping to prove that there is no silicon inside (that's what I expect).
Unfortunately I've broken it in too many pieces.
On the NEC PC1237 datasheet it states that the chip works with a supply voltage from 25-60Volts. As you are using it at 20v I suspect that has more to do with problems your are encountering than counterfeit chips. I am bemused as to why anyone would bother to fake a £1 chip.
Indeed, but they even fake T092 transistors for how much profit? Member Ilimzn has given us an idea of the reasons behind the proliferation and the different types of fakes from the many Chinese fabs now also churning out our genuine popular semis too.
Let's just say it's can be a "creative" way to dispose of and get some return on substandard products that would formerly have been destroyed. Why do we shop at their known outlets for unobtanium products, begging for fakes and then complain about getting them? To me, that is the real bemusement.
This is very old thread, but referring to Zeons schematic. I do not know how to calculate R10 to ground. Can someone help me?
J
The chip works with the stated voltage through a series resistor to the supply pin, as it has an internal shunt reg. Did you take that into account?
Jan
I did.
As I've updated in my post #46 and #50, I've replaced the new faulty 1237 with an old original from an Akai amplifier. The board then worked as it should, without any other changes.
So the counterfeits were the only problem there.
As for the equivalent circuit, I gave up on that, I'll simply avoid uPC1237 in the future.
Perhaps you refer to the schematic in post #12.
R10 is series with the relay. So you need to now the ratings of the relay's coil.
For instance you can get the voltage (V) and power (W) from the datasheet.
Example:
Let's say your power supply is Vdd=30Vcc.
Also let's say your relay is V= 12V and P= 0.4w. This means the current through the coil when it's on, is
/V =0.4/12 A, or 33mA .You will have to have this current through R10 as well.
Also the voltage across R10 has to be Vdd - 12V, that is 18V in this case.
R = U/I , so you need 18/0.033 ohms, or 545 ohms. I think you can use a 570ohm here.
The dissipated power in R10 is U*I, that is 18V * 33mA = 0.6W . Use a 1W or bigger resistor.
Of course you can do this by trial and error, pretty much. Start with a high value resistor, like 1K, and lower it experimentally until you have the correct voltage on your relay. Use 2W resistors and you're done.
Perhaps you refer to the schematic in post #12.
R10 is series with the relay. So you need to now the ratings of the relay's coil.
For instance you can get the voltage (V) and power (W) from the datasheet.
Example:
Let's say your power supply is Vdd=30Vcc.
Also let's say your relay is V= 12V and P= 0.4w. This means the current through the coil when it's on, is
You will have to have this current through R10 as well.
Also the voltage across R10 has to be Vdd - 12V, that is 18V in this case.
R = U/I , so you need 18/0.033 ohms, or 545 ohms. I think you can use a 570ohm here.
The dissipated power in R10 is U*I, that is 18V * 33mA = 0.6W . Use a 1W or bigger resistor.
Of course you can do this by trial and error, pretty much. Start with a high value resistor, like 1K, and lower it experimentally until you have the correct voltage on your relay. Use 2W resistors and you're done.
Right on spot! Thanks ceteras.
I just ordered these chips few weeks from ges electronic.
J
Hello Alex,Hi,
my pcb with DC prot.and soft startAn externally hosted image should be here but it was not working when we last tested it.thank u zeonrider
May you please post the pcb layout and dimension for this board (softstart with speaker)
Thank in advance.
AD
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.