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I powered up the jackal board alone without the CPU/audio board. ?I don’t have the fancy equipment(yet) to do the audio signal measurements & such. ?However I did the basic checking of the current draw which is 90mA, and the 3.3v & 5v supply circuits with a DMM which check out fine. ?Then I started poking around the rest of the test points and CPU sockets and see 11.7v on some of the CPU socket pins as seen in the attached photo. ?From what I understand the Teensy 3.6 pins are 3.3v tolerant and because of this I am hesitant to connect the CPU. ?However my friend’s board measures the same so I’m thinking there may be no problem. ?Just curious why the high voltage readings with no CPU connected and is this okay?  Jim Zdunic KM4TXR
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I've just started gathering the parts for this project, but I noticed a detail that might be a factor in your measurements. The Bag of Parts file contains the following line. This is also what appears on page 26 of the current version, ver 16, of manual section 2:
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5V, 1.5A voltage regulator, TO-220
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LM7812CT/NOPB-ND? (Digikey)
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Please note that the LM7812 is NOT a 5V regulator, it's a 12V regulator. If you used the LM7812 instead of an LM7805, which IS a 5V regulator, then you might see approximately the voltage that you measured. This would exceed the Teensy's supply voltage spec.
Also in version 16 of manual section 2, on page 32, is a schematic section called "Voltage Regulators", which shows that Teensy +5V should come from an LM7805, not an LM7812.
I haven't found an LM7812 anywhere in the schematics. Make sure you've got an LM7805 and not an LM7812 at U2, the 5V REGULATOR location on the board. Also note that the BOM on page 25 has the +5v regulator listed as U4 rather than U2 as shown on the schematic.
My JackAl board doesn't show the U1, U2 part numbers in the legends that are printed on the circuit board- These locations are identified as "5V REGULATOR" and "3.3V REGULATOR".
U1, the +3.3V regulator, is shown in the schematic as an LM1117-33, but the 3.3V regulator in the part list of pate 26 is given as an LM1086-3.3. These are interchangeable, with same pinout and same noise spec, and slightly better input ripple rejection for the LM1117-3.3.
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Sorry Mike, I thought we posted that correction. I'll check into it.
Jack, W8TEE
On Sunday, March 3, 2019, 8:50:03 AM EST, Mike WA7EXH <linse@...> wrote:
I've just started gathering the parts for this project, but I noticed a detail that might be a factor in your measurements. The Bag of Parts file contains the following line. This is also what appears on page 26 of the current version, ver 16, of manual section 2:
|
5V, 1.5A voltage regulator, TO-220
|
LM7812CT/NOPB-ND? (Digikey)
|
Please note that the LM7812 is NOT a 5V regulator, it's a 12V regulator. If you used the LM7812 instead of an LM7805, which IS a 5V regulator, then you might see approximately the voltage that you measured. This would exceed the Teensy's supply voltage spec.
Also in version 16 of manual section 2, on page 32, is a schematic section called "Voltage Regulators", which shows that Teensy +5V should come from an LM7805, not an LM7812.
I haven't found an LM7812 anywhere in the schematics. Make sure you've got an LM7805 and not an LM7812 at U2, the 5V REGULATOR location on the board. Also note that the BOM on page 25 has the +5v regulator listed as U4 rather than U2 as shown on the schematic.
My JackAl board doesn't show the U1, U2 part numbers in the legends that are printed on the circuit board- These locations are identified as "5V REGULATOR" and "3.3V REGULATOR".
U1, the +3.3V regulator, is shown in the schematic as an LM1117-33, but the 3.3V regulator in the part list of pate 26 is given as an LM1086-3.3. These are interchangeable, with same pinout and same noise spec, and slightly better input ripple rejection for the LM1117-3.3.
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Hello Mile,
Thank you for mentioning this to try and help me. This is no longer an issue for me and I figured I’d post up the findings to close the loop on this:
I spoke with Al about my measurements and after checking a few things concluded that there was nothing wrong. ?The near 12v readings were simply floating voltages in open circuits because the CPU wasn’t installed. ?This was determined by using an ohm meter
and measuring back to the 12v supply circuit which did not show and low resistance.
Jim KM4TXR
On Mar 3, 2019, at 8:51 AM, jjpurdum via Groups.Io < jjpurdum@...> wrote:
toggle quoted message
Show quoted text
Sorry Mike, I thought we posted that correction. I'll check into it.
Jack, W8TEE
On Sunday, March 3, 2019, 8:50:03 AM EST, Mike WA7EXH < linse@...> wrote:
I've just started gathering the parts for this project, but I noticed a detail that might be a factor in your measurements.
The Bag of Parts file contains the following line. This is also what appears on page 26 of the current version, ver 16, of manual section 2:
|
5V, 1.5A voltage regulator, TO-220
|
LM7812CT/NOPB-ND?
(Digikey)
|
Please note that the LM7812 is NOT a 5V regulator, it's a 12V regulator. If you used the LM7812 instead of an LM7805, which IS a 5V regulator, then you might see approximately the voltage that you measured. This would exceed the Teensy's supply voltage spec.
Also in version 16 of manual section 2, on page 32, is a schematic section called "Voltage Regulators", which shows that Teensy +5V should come from an LM7805, not an LM7812.
I haven't found an LM7812 anywhere in the schematics. Make sure you've got an LM7805 and not an LM7812 at U2, the 5V REGULATOR location on the board. Also note that the BOM on page 25 has the +5v regulator listed as U4 rather than U2 as shown on the schematic.
My JackAl board doesn't show the U1, U2 part numbers in the legends that are printed on the circuit board- These locations are identified as "5V REGULATOR" and "3.3V REGULATOR".
U1, the +3.3V regulator, is shown in the schematic as an LM1117-33, but the 3.3V regulator in the part list of pate 26 is given as an LM1086-3.3. These are interchangeable, with same pinout and same noise spec, and slightly better input ripple rejection for
the LM1117-3.3.
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Has anyone measured the 12V current, 5V current & 3V? current?
John
N2NOL
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It is not very likely anyone has measured the current draw from the 5v and 3.3v regulators because you would have to take them out of the jackal circuit to add an any amp measuring device between them and the circuits they provide power to.
Just curious, why you are asking?
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Both of the regulators are linear and get hot.? The heat could be better dissipated with a series resister with a heat sink to the chassis.? PCB's don't do well with heat coupled to them (via the device leads).? If the 5V reg could stand the extra current, it might be better to source the 3V power from the 5V instead of 12V.
I would have measured it myself but I am still inquiring parts and have not started the build.? I also might wait for the revised manual to make it an easier task.
John N2NOL
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What I can tell you is the 3.3v reg gets quite hot with the 7” display. ?The heat sink shown in the photo below gets so hot you can’t touch it for more than a second or two before the hot stove sensation sets in.  The 5v reg hardly warms up the heat sink. Jim ?KM4TXR
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Sorry if you've already answered this.
It looks your 3.3V and 5V regulator heat sinks are shorting.
Did you use an insulator on the 3.3V regulator?
John
W1JDS
On 3/3/2019 5:44 PM, James Zdunic wrote:
toggle quoted message
Show quoted text
What I can tell you is the 3.3v reg gets quite hot with the 7”
display. ?The heat sink shown in the photo below gets so hot you
can’t touch it for more than a second or two before the hot stove
sensation sets in.
The 5v reg hardly warms up the heat sink.
Jim ?KM4TXR
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You should insulate the 3.3V regulator’s tab from the heat sink including the screw.?
toggle quoted message
Show quoted text
On Mar 3, 2019, at 6:49 PM, John Sutter < jds@...> wrote:
Sorry if you've already answered this.
It looks your 3.3V and 5V regulator heat sinks are shorting.
Did you use an insulator on the 3.3V regulator?
John
W1JDS
On 3/3/2019 5:44 PM, James Zdunic wrote:
What I can tell you is the 3.3v reg gets quite hot with the 7”
display. ?The heat sink shown in the photo below gets so hot you
can’t touch it for more than a second or two before the hot stove
sensation sets in.<FF7C50BA_6666_431C_9EF8_A01940D2F7D6.jpeg>
The 5v reg hardly warms up the heat sink.
Jim ?KM4TXR
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Thanks for the tip. ?I didn’t realize the heat sink tab is Vout on 3v regulators. ?I placed a piece of rubber between them until I get an insulator for it.
Jim ?KM4TXR
On Mar 3, 2019, at 9:05 PM, PeteWK8S via Groups.Io < pmeier@...> wrote:
toggle quoted message
Show quoted text
You should insulate the 3.3V regulator’s tab from the heat sink including the screw.?
On Mar 3, 2019, at 6:49 PM, John Sutter < jds@...> wrote:
Sorry if you've already answered this.
It looks your 3.3V and 5V regulator heat sinks are shorting.
Did you use an insulator on the 3.3V regulator?
John
W1JDS
On 3/3/2019 5:44 PM, James Zdunic wrote:
What I can tell you is the 3.3v reg gets quite hot with the 7” display. ?The heat sink shown in the photo below gets so hot you can’t touch it for more than a second or two before the hot
stove sensation sets in.<FF7C50BA_6666_431C_9EF8_A01940D2F7D6.jpeg>
The 5v reg hardly warms up the heat sink.
Jim ?KM4TXR
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They should not touch.
Jack, W8TEE
On Sunday, March 3, 2019, 8:49:26 PM EST, John Sutter <jds@...> wrote:
Sorry if you've already answered this.
It looks your 3.3V and 5V regulator heat sinks are shorting.
Did you use an insulator on the 3.3V regulator?
John
W1JDS
On 3/3/2019 5:44 PM, James Zdunic wrote:
What I can tell you is the 3.3v reg gets quite hot with the 7”
display. ?The heat sink shown in the photo below gets so hot you
can’t touch it for more than a second or two before the hot stove
sensation sets in. 
The 5v reg hardly warms up the heat sink.
Jim ?KM4TXR
|
jjpurdum