Stereo memory man with hazarai - Two IC’s have fried!
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Posted: 02 March 2017 06:52 AM

Hi All,

Hoping that someone on the forum can help me out. To cut a long story short, the box was plugged into a 24v power supply rather than the correct 9v.

As you can all probably imagine my little box didn’t like this very much, smoke coming from inside…

After inspection and finally removing the PCB from the case. I need the spec on two components if someone can help. There are two IC’s positioned at U12 and U13 on the PCB, could someone tell me what they are as both of mine have melted so I cannot see what is written on them.

I contacted EHX support through their website and they will only have it in to inspect, they won’t supply me with a parts list or diagram to help. I am based in the UK, parts should be easy to get hold of, I just need to know the correct value’s for the components that have cooked!

Even if someone would be so kind as to remove the 4 x rear screws and take a picture of the IC’s located to the top left of the box, near the power input, as mentioned U12 and U13. I have googled for images and zoomed as much as I can but still having trouble making out the spec’s written on the components. I have uploaded a pic and circled the components in red.

Huge thanks in advance for reading! Really appreciate any help!

Cheers, Dave.

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Posted: 06 March 2017 09:22 AM | Link to this reply (#1)

U12 = On Semiconductor CS51413GD, don’t buy the CS51413E version.
U13 = ST L78M05CDT-TR

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Posted: 06 March 2017 01:29 PM | Link to this reply (#2)
Flick (EHX Staff) - 06 March 2017 09:22 AM

U12 = On Semiconductor CS51413GD, don’t buy the CS51413E version.
U13 = ST L78M05CDT-TR

Thanks so much for your help!!

The original semiconductor is now obsolete, this is about as close as i can find here available at Mouser..
http://www.mouser.co.uk/ProductDetail/ON-Semiconductor/NCV51411DR2G/?qs=8sOby8ZxZLEoi7+IyE1+8g==

Do you think it may do the trick? Hats off to you for the info!

Dave smile

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Posted: 06 March 2017 02:10 PM | Link to this reply (#3)

The NCV51411DR2G should work fine but we have never tested it.

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Posted: 06 March 2017 07:27 PM | Link to this reply (#4)
Flick (EHX Staff) - 06 March 2017 02:10 PM

The NCV51411DR2G should work fine but we have never tested it.

Huge thanks again for the fast reply and help, I will try and let you know if it works or not. Cheers, Dave.

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Posted: 20 March 2017 11:32 AM | Link to this reply (#5)
Flick (EHX Staff) - 06 March 2017 02:10 PM

The NCV51411DR2G should work fine but we have never tested it.

Hi again Flick,

Still no joy, the only chip I could get hold of was this one CS51414EDR8G ...http://uk.farnell.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=15001&langId=44&urlRequestType=Base&partNumber=1652426&storeId=10151

There is no ‘sync’ leg on this component. Power to the unit and still nothing. I had spoken with John Williams here and he thinks that the unit is a write off.

Hope you could maybe shed some light on the above part…?

Thanks in advance for your reply.

Dave.

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Posted: 20 March 2017 12:07 PM | Link to this reply (#6)

The CS51414 should work since we don’t use the SYNC, BIAS or SHDNB pins but the IC you bought is the “E” version which we have had problems with regards to CS51413E. Did you measure the output voltage on the left side of L2 after changing this IC? I’m curious to know what voltage it is producing.

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Posted: 20 March 2017 05:11 PM | Link to this reply (#7)
Flick (EHX Staff) - 20 March 2017 12:07 PM

The CS51414 should work since we don’t use the SYNC, BIAS or SHDNB pins but the IC you bought is the “E” version which we have had problems with regards to CS51413E. Did you measure the output voltage on the left side of L2 after changing this IC? I’m curious to know what voltage it is producing.

Hi Flick,

I didn’t ignore your ‘don’t get the E version’ in your first replies. I am struggling to get the correct IC and the E version seems to be the only available in stock at UK retailers at the moment. Mouser has a lead time of 26 weeks for for the NCV51411DR2G.

OK, my diagnostics are not good at all but I’ve had the multimeter out on VDC…

FB7 - 11.85v
D12 - 11.85v - 3.61v
U12 - 3.35v (Top pin 4) 3.6v (Bottom pin 2)
D13 - 0v
L2 - 0v
U13 - 3.6v (Top pin) 1.26v (Bottom pin)

Not sure if that means anything to you there. I’m unsure if it’s the IC not giving them what they need or other components are damaged.

Thanks, Dave.

 

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Posted: 21 March 2017 09:47 AM | Link to this reply (#8)

FB7 is the voltage used to power the unit. Are you using 12V?

The voltage across D12 should be somewhere between 0.2V and 0.5V but it looks like you’re measuring over 8V. It’s possible D12 is no good and has burned out forming a resistor. You could try measuring D12’s forward voltage when the unit is powered down.

Since D12 is dropping so much voltage, the CS51414 is not getting a high enough voltage to be powered on correctly. The datasheet says it needs 4.5V but it is getting only 3.6V.

If you determine that D12 is bad, you could remove D12 and short out its two pads as a test to see if the rest of the circuitry is working normally. If it is fine with D12 shorted then replace D12.

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Posted: 21 March 2017 08:25 PM | Link to this reply (#9)
Flick (EHX Staff) - 21 March 2017 09:47 AM

FB7 is the voltage used to power the unit. Are you using 12V?

The voltage across D12 should be somewhere between 0.2V and 0.5V but it looks like you’re measuring over 8V. It’s possible D12 is no good and has burned out forming a resistor. You could try measuring D12’s forward voltage when the unit is powered down.

Since D12 is dropping so much voltage, the CS51414 is not getting a high enough voltage to be powered on correctly. The datasheet says it needs 4.5V but it is getting only 3.6V.

If you determine that D12 is bad, you could remove D12 and short out its two pads as a test to see if the rest of the circuitry is working normally. If it is fine with D12 shorted then replace D12.

Hi Flick, Thanks again for your help.

OK, adjusted power supply to get the following…

FB7 - 9.7v
D12 - Shorted
U12 - 8.22v - 9.6v
D13 - 2.77v - 0.007v
L2 - 2.7v - 2.68v
U13 - 9.7 - 4.95v

After shorting D12 there was no change in operation and i moved onto D13….

With the very low 0.007v on the one side of D13 I thought maybe I should short that also. So I did, L2 then read pretty much 0v each side, I re soldered D13, I didn’t take note of which way it came off (school boy error) but matched it up visually with one further down near the main chip in the centre. Re-powered the unit and U12 popped again smile

Having lots of fun with this little board.

Hopefully some of my errors may help with you knowing what kind of voltage was hitting L2 from the IC as mentioned in your previous post.

All the best, Dave.

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Posted: 23 March 2017 09:02 AM | Link to this reply (#10)

It seems like U12 is closer to working properly but still not quite there. It appears to be making 2.7V instead of the required 3.3V. This might be do to the “E” version of the chip but that is a guess. You could try lowering R18, which is 100 ohms right now, to something like 75 ohms. I would advise putting another resistor in parallel with R18 to lower its value. Try 330 ohms in parallel with R18.

Regard D13: unlike D12, D13 should have significantly more voltage across it, in fact the voltage across D13 will be close to the output voltage which is ideally 3.3V.

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