Quantar conversion

[ldanna]

My radio club was donated several Quantar satellite receivers . these appear as a regular Quantar chassis with a receiver, wireline card and a low power power supply. I reasoned I could add the higher power supply an exciter and power amp and voila a quantar repeater. Well all seamed OK The unit was programmed as a repeater . the receiver worked it would key the transmitter which outputted 100 watts . the problem is no repeated audio and no PL generated. After lots of testing I found that replacing the SCM module from a real repeater solved the problem . So why doesn't the original SCM pass audio? the local speaker works but no audio out the repeater. Is this a firmware issue ? or a hardware issue. I would like to solve this without locating new SCM cards

Thanks for any help out there

Larry

[Bill_G]

Cuz it was sold as a receiver. Didn't need xmit audio. So, they didn't put it in. It's a value added option.

[ldanna]

Is it possible to add it after the fact?

Larry

[Bill_G]

You could try swapping in just the memory cards and firmware. There are folks who have figured out how to reprogram the feature sets sold to a serial number, but I don't know how.

[ldanna]

are the features programmed into the 4 chips u651 - u 654? on older boards or the SIMM on newer boards or in another chip maybe the Codeplug? Very confusing

[Bill_G]

If your rcvr SCM has the same part number as your xmit SCM, swap the simms to see if that works. But, if they are different, then don't. There will be a CLN number printed on the boards someplace. Not to be confused with the serial number which usually is a CAE number.

[d119]

Larry,

Did you change the "Hardware Platform" from "Quantar Satellite Receiver" to "Quantar" in the RSS under the "Hardware Configuration" tree? I'm certain you did, but just in case... I was always under the impression these used the same SCM's as standard Quantar stations, ASTROTAC receivers, etc.

I am 99.9% sure I've used the ASTROTAC receiver SCM in a Quantar station and it worked fine without any modifications to anything other than the hardware platform setting.

[Bill_G]

Good thought. Certainly worth a shot. If he used a working repeater codeplug, the hardware config page should have been set to rptr.

As far as I can tell, Quantar full stations and rcvrs used the same SCM, and your only limititation was what vintage of Quantar it was in. There were like five major builds, each with their own various simms and firmware chips that couldn't be swapped between versions. Anyone that has had to upgrade Fed equipment has gone through the procedure to upgrade stations to incorporate a new feature, and sometimes new SCM's were in the kit (along with logs and tracking files so you have to surrender every board you swap out). But, it wouldn't surprise me if at one point MOT didn't hard code rcvrs as just receivers to get a different price even though all the discrete parts were present on each board.

[Astro Spectra]

I have made a Satellite Receiver into a portable Quantar (adding a backplane extension cable to an exciter) and just re-configured the SCM hardware platform settings.

[d119]

Backplane extension cable?

[Astro Spectra]

You need to solder the appropriate signals to a connector for the exciter. I cut down a PCI bus connector for the job and used the backplane table in the Quantar detailed schematics to get the pin out. Fortunately most pins are ground but you still have bunch of signals to pick off. You end up with a DIY PD3500. The exciter module sits atop the receiver and you'll need a small PA, I used a PA module as I only wanted 10W out.

[Astro Spectra]

Just to Bill's point, the Quantar is an incredibly flexible platform. The backplane has chip that IDs the station type and S/N (looks like a small plastic TO92 transistor on older units). Despite that you can program it to be whatever you want (hardware platform type as d119 pointed out), you'll get errors on validation but it will still try and function.

Now to your specific issue, there are some SCM types (EPIC IV?) that do not support analog audio and some well known SCM faults that affect audio.

[Astro Spectra]

Here's the skinny on the fault:

http://communications.support/threads/3 ... SCM-SOLVED!

[ldanna]

Il try swapping the U306b chip to see if that works
Ive gotten the audio back by swapping SCM boards but cannot get the origional board to work
Problem looks like a SCM board issue. Tried other firmware with same dissapointing results


Larry

[d119]

Curious if perhaps the station you got doesn't have the original SCM in it, and you perhaps got a data-only SCM in it. As far as I know, an EPIC is an EPIC is an EPIC (with respect to the different versions), and should be usable across platforms without modification. When you start getting into the DATATAC SCM's is where you end up with unexpected results.

Bet someone swapped out those SCM's before you got the receivers.

I also would not mess with the backplane ID device. All it is is a unique number, it doesn't affect what the station is capable of, it just interlocks firmware upgrades, etc. I've successfully converted platforms (DataTAC to Quantar, Quantar RX to Quantar Station) without having to do anything with that device.

[d119]

Here's the skinny on the fault:

http://communications.support/threads/3 ... SCM-SOLVED!

Thanks for that - I have one exhibiting that very problem that I had to swap out - just ordered a couple of MAX292EWE's... Hopefully that'll fix it - MUCH OBLIGED!

[ldanna]

Well I am using an origional chassis with the origional SCM, Pwr supply, Wireline and receiver just as it came from the factory. We were given 6 of these satellite receivers. I added an exceiter, power amp, and replacd the power supply to handle the extra power needed for the system. Then reprogrammed the SCM as a repeater. the hardware validation showed no conflicts. I thought I was home free. I keyed up the repeater with a walkie. the repeater came to life with full power and the appropiate drop out delay programmed in. Then I talked and no audio was repeated .
Courious I tried 2 other SCM modules from the other receivers and same results . Only when I swapped with a known good SCM did it work as expected. that's why I was into swapping firmware chips . no joy there either. could be the U306 chip failed on more than one unit. I'll keep posting as I continue my experiments

Larry

[ldanna]

Another note Local audio from a Mic also showed no audio

LArry

[d119]

Have you done a full alignment?

[ldanna]

Update. Tried a 4th SCM from yet another receiver. Same results can't believe the problem is with the chip, not in 4 boards. I tried to do an alignment. reference modulation, no modulation square wave. Tried to do deviation alignment no audio either . Both parameters good on my working SCM.
is there another alignment procedure I am missing?

Any more ideas someone can come up with am close to wits end

[Astro Spectra]

What are the SCM part numbers you have? What are the firmware version of the SCM, WL, and Exciter?

[Astro Spectra]

Oh, and just as a double check for out of left field what is the P/N of the backplane?

[xmo]

If your stations have Epic-III Station Control Modules and you are programming amateur frequencies that are out-of-band - that would be your problem.

You could try programming an in-band frequency and check the TX audio there.

[ldanna]

Am at work so ll check the numbers this evening. The TX is 403-433 R1 . I am seting it up to TX in the 425Mhz portion of the amateur band That should not be out of band for this split I believe or did Motorola do some thing weird? My goal is 4 repeaters all recieving 0n 444 and transmiting on 425 as links for our main repeater which will vote the 4 sites

Larry

[ldanna]

I did copy down the firmware and was able retrieve i. t here it is. Backplane info this evening. Firmware is out of date for this system but they do match up.
SCM: 16.06.018
WL: 16.06.013
EXC: 13.05.002

SCM:
U651 5191020L05
U652 5191020L06
U653 5191020L07
U654 5191020L08
WL:
U134 5191013H70
U135 5191013H69
EXC:
U3701 5191013P14

[Bill_G]

This is supporting my idea the boards are hard coded as receiver only. But, we'll see what happens when he tests them back in their original band.

[DarkHelmet]

I've done this, it will work.

What is the PN on the SCM you have? There is a fixed part which selects data only, IR or conventional.

The boot firmware of the Quantar conventional, Astrotac, and Intellirepeater are all different and will prevent the rest of the code booting.

What happens if you put the SCM that doesn't work in known working quantar station?

You may want to upgrade your code to the 20.x series too, check out ebay.

This stuff really ain't that complex, the quantar is a really easy design to troubleshoot/modify. I mean Motorola even used a halfway decent RTOS (PSOS+ was decent for 1990!)

[ldanna]

PN is TTN4094 B 03 CA11YH9. firmware is on 4 32 pin chips on main board
Where is the backplane ID located I could not find it .
the chassis label notes on one Professional receiver 5N77 but I have another gold chassis which the label says
Professional Transceiver 5N77.
Putting the non working board in the newer chassis (marked Professional Transceiver) yields same results. no audio
tomorrow I am picking up hopefully a working unit with same board with same firmware that mine is and going to compare with that one
More to come

LArry

[DarkHelmet]

PN is TTN4094 B 03 CA11YH9. firmware is on 4 32 pin chips on main board

OK, great this is a EPIC 1 board (no difference functionality between EPIC 1/2/3,5). The 4094 EPIC 1 boards are special as they have the a dip switch to let you use a flash part in place of the 27c040 OTP parts. Makes it easy to upgrade to new code.

Where is the backplane ID located I could not find it .

It's in the RSS. You don't need it for this, doesn't matter.

Putting the non working board in the newer chassis (marked Professional Transceiver) yields same results. no audio

This sounds like the U306 problem. The SCM may have an issue with a bad chip, it's known to happen on the older SCM's. Might want to checkout the service manual excerpt too.

Question, does this SCM have individual colored LEDs on the front or a light pipe going to SMD LEDs?

If I had to put money on it, I bet that's your issue, or at least in that circuity. Are you comfortable and do you have the tools to work with 0805 SMD parts?

[ldanna]

OK I got the other Quantro from a friend coursly enough same Firmware revision as mine . his unit had audio but very low almost nill but I could discern some audio. Of course my boards did not work at all. I am on board with the U306 diagnosis. I will order some chips to try it out.

The board has the light pipes.
I am interested in the dip switch mentioned I see a 4 position one, is there info on it's functions? or are there any jumper locations ? I know M likes those
0 Ohm resisters


No problem working with SM components I have a hot air rework station and have removed and put new chips on boards before.

LArry

[ldanna]

Update: Ordered new chips for U 306 waiting for them to arrive

LArry

[d119]

So I replaced the U306 on the board I have that was having no TX audio or TX PL problems, and sure enough that was the problem! That board is back in service now. Thanks all!

[ldanna]

Update again. Got new U306 chips in from Digikey. Replaced chip in non working board and still no audio.
Found partial schematics for SCM board and checked for audio at U 311 If I remember the number correctly ( the Soft Pot chip ) that feeds the VCO and Ref modulation to the exciter. I could see a bit of audio at the input of the chip and absolutely no audio coming out of the chip. Could the chip be bad or is there some setting controlling the soft pots that needs to be adjusted. I tried a deviation alignment, no audio. also no modulation in the reference modulation alignment. As a check I went back to the good board and had good audio out of the chip. Is there an adjustment or setting I am missing? I think Ill order new soft pot chips next


LArry

[DarkHelmet]

Update again. Got new U306 chips in from Digikey. Replaced chip in non working board and still no audio.

Did you do any testing or did you blindly replace the chip? It's actually easy to boot the cards on their own or connect them to a PCI bus extender for testing.

Found partial schematics for SCM board and checked for audio at U 311 If I remember the number correctly ( the Soft Pot chip ) that feeds the VCO and Ref modulation to the exciter.

Did you not see the link I gave you above? It's the complete 4094 SCM schematic diagram as a PDF.

I could see a bit of audio at the input of the chip and absolutely no audio coming out of the chip. Could the chip be bad or is there some setting controlling the soft pots that needs to be adjusted. I tried a deviation alignment, no audio. also no modulation in the reference modulation alignment. As a check I went back to the good board and had good audio out of the chip. Is there an adjustment or setting I am missing? I think Ill order new soft pot chips next

I would trace backwards on the VCO AUDIO line, most of the parts in line are easy to troubleshoot on their own. Check out the REF AUDIO line too, if it's the same as the VCO AUDIO you have a problem further back in the chain.

[NickLawson]

Did you change the "Hardware Platform" from "Quantar Satellite Receiver" to "Quantar" in the RSS under the "Hardware Configuration" tree?
I'm certain you did, but just in case.
I was always under the impression these used the same SCM's as standard Quantar stations, ASTROTAC receivers, etc.