Is there any sort of recommended power up sequence for the FV 1?
I've got a split rail using two LDO 3.3v regs. They can handle about 100ma each. With an FV1 soldered on to the board, my 3.3v rails get sucked down to about 1 volt DC, even at the input of the regs. With no FV1 the rails are exactly where they should be. My bench supply is rated for 1400ma. I've been troubleshooting this for over a week now; the FV1 seems to be the culprit. Any thoughts?
Power up sequence?
Moderator: frank
Re: Power up sequence?
Sounds like there may be a short somewhere. Have you checked for continuity between FV-1 pins that shouldn't have continuity.
www.stanleyfx.co.uk
"It's fairly straight forward, if you want to start it press start, you can work out the rest of the controls yourself."
"It's fairly straight forward, if you want to start it press start, you can work out the rest of the controls yourself."
Re: Power up sequence?
Thanks for the reply.
No shorts, but I discovered that the FV1's RefN and its neighboring GND pins are floating unconnected to my ground pour. I'll remedy that and see if it fixes the issue.
No shorts, but I discovered that the FV1's RefN and its neighboring GND pins are floating unconnected to my ground pour. I'll remedy that and see if it fixes the issue.
Re: Power up sequence?
Hmm, there's no change. Both 3.3v rails sag down to 1v once they're connected to the FV1. No other (analog supply) rails are affected.
Re: Power up sequence?
I've switched from the dual 100ma LDO's to a beefier LDO, the AMS1117, set up for a 3.3v output.
Unloaded I get 3.3vdc as expected. When connected to the FV1 I get sag, but not as much. I get about 2.5vdc.
It's worth noting that nothing runs unusually warm when power is hooked up to the FV1, everything sits around 70 deg F.
Any thoughts at all? Aside from the floating Neg Ref and GND pins that I corrected earlier, nothing seems to be amiss.
Unloaded I get 3.3vdc as expected. When connected to the FV1 I get sag, but not as much. I get about 2.5vdc.
It's worth noting that nothing runs unusually warm when power is hooked up to the FV1, everything sits around 70 deg F.
Any thoughts at all? Aside from the floating Neg Ref and GND pins that I corrected earlier, nothing seems to be amiss.
Re: Power up sequence?
Check the pads on the PCB and make sure than none are accidentally connected to the wrong rail. You may want to list the pad and voltage your are seeing, with the chip removed, so we can all look at it.
Frank Thomson
Experimental Noize
Experimental Noize
Re: Power up sequence?
Maybe a picture of the PCB area around the FV-1 or PCB layout around the FV-1 to see if any of us can spot any possible problems will help.
www.stanleyfx.co.uk
"It's fairly straight forward, if you want to start it press start, you can work out the rest of the controls yourself."
"It's fairly straight forward, if you want to start it press start, you can work out the rest of the controls yourself."
Re: Power up sequence?
Guys I really appreciate the help. Hopefully I can be as helpful in the future as people on this forum have been to me.
I think I've solved the issue (hopefully). I found a tiny solder blob shorting across XO's. I inadvertently had an over voltage condition to the FV1 for about 45 seconds so I'm sure something is damaged.
Here's a table of voltages (after the OV condition)
pin1 0v
pin2 0.30vdc (it's floating)
pin3 1.64vdc
pin4 0vdc
pin5 0vdc
pin6 3.32vdc
pin7 0vdc
pin8 3.32vdc
pin9 1.44vdc
pin10 1.22vdc
pin11 0vdc
pin12 0vdc
pin 13 0vdc
pin 14 3.3vdc (I'm running the FV1 in "hardware" mode on the internal ROMs, the micro footprint is on the PCB but not installed, thus the 3.3vdc)
pin15 3.3vdc (see above)
pin16 3.3vdc
pin17 3.3vdc
pin18 3.3vdc
pin19 0vdc
pin20 3.3vdc (control pot)
pin 21 0.67vdc (control pot)
pin22 3.3vdc (control pot)
pin23 3.3vdc
pin24 0vdc
pin25 0vdc
pin26 3.3vdc
pin27 1.65vdc
pin28 1.65vdc
Let me know if you spot any issue; I'll post board layout after I eat lunch.
Matt
I think I've solved the issue (hopefully). I found a tiny solder blob shorting across XO's. I inadvertently had an over voltage condition to the FV1 for about 45 seconds so I'm sure something is damaged.
Here's a table of voltages (after the OV condition)
pin1 0v
pin2 0.30vdc (it's floating)
pin3 1.64vdc
pin4 0vdc
pin5 0vdc
pin6 3.32vdc
pin7 0vdc
pin8 3.32vdc
pin9 1.44vdc
pin10 1.22vdc
pin11 0vdc
pin12 0vdc
pin 13 0vdc
pin 14 3.3vdc (I'm running the FV1 in "hardware" mode on the internal ROMs, the micro footprint is on the PCB but not installed, thus the 3.3vdc)
pin15 3.3vdc (see above)
pin16 3.3vdc
pin17 3.3vdc
pin18 3.3vdc
pin19 0vdc
pin20 3.3vdc (control pot)
pin 21 0.67vdc (control pot)
pin22 3.3vdc (control pot)
pin23 3.3vdc
pin24 0vdc
pin25 0vdc
pin26 3.3vdc
pin27 1.65vdc
pin28 1.65vdc
Let me know if you spot any issue; I'll post board layout after I eat lunch.
Matt
Re: Power up sequence?
Hi Matt, all those voltages look ok. do you have any of your pots connected to the FV-1 circuit, if so set them at midway point and take a voltage reading to make sure you get 1.65v appx. Pins 15/16 read approx. half supply voltage but I do have those connected up to external EEPROMS.
Have you tried a new FV-1 IC in place ?
Have you tried a new FV-1 IC in place ?
www.stanleyfx.co.uk
"It's fairly straight forward, if you want to start it press start, you can work out the rest of the controls yourself."
"It's fairly straight forward, if you want to start it press start, you can work out the rest of the controls yourself."
Re: Power up sequence?
I read DC on the control pins about 1.65v with the three external pots set at halfway point. In the prior reading the pots were set to nearly max open or closed, which is why those pins read the way they do.
Unfortunately I only have one FV1; this is rather foolish of me I realize. I picked up one from an overpriced third party vendor because I didn't want to bug Frank with a one or two piece order, LOL.
Matt
Unfortunately I only have one FV1; this is rather foolish of me I realize. I picked up one from an overpriced third party vendor because I didn't want to bug Frank with a one or two piece order, LOL.
Matt
Re: Power up sequence?
I think a board layout may help a lot.
Does the analogue part of the circuit work correctly with the FV-1 removed, with no FV-1 in place you can solder a link from the pads of 1+2 to whatever output you are using 27or28. Test the full audio path that way.
Does the analogue part of the circuit work correctly with the FV-1 removed, with no FV-1 in place you can solder a link from the pads of 1+2 to whatever output you are using 27or28. Test the full audio path that way.
www.stanleyfx.co.uk
"It's fairly straight forward, if you want to start it press start, you can work out the rest of the controls yourself."
"It's fairly straight forward, if you want to start it press start, you can work out the rest of the controls yourself."
Re: Power up sequence?
Analog chain works but FV-1 doesn't pass audio. I don't know if it's the part or if the XO isn't oscillating.
My troubleshooting is complicated by the fact that we recently moved to a new house, and all my test gear is packed in various boxes. It took me all week to locate my oscilloscope, but I can't seem to find my probes, LOL. I can't locate my audio analyzer anywhere, and my frequency counter is also MIA, ha.
One thing at a time, but I'll ping Frank again and order some spare FV1's from him.
My troubleshooting is complicated by the fact that we recently moved to a new house, and all my test gear is packed in various boxes. It took me all week to locate my oscilloscope, but I can't seem to find my probes, LOL. I can't locate my audio analyzer anywhere, and my frequency counter is also MIA, ha.
One thing at a time, but I'll ping Frank again and order some spare FV1's from him.