Based upon input from the Forum, it seems a good bet that diminished brightness of the display on Systems 9000 control heads could be the fault of leaking capacitors. This is with uniform reduction of brightness and not from bad or missing segments.
Does anyone have the part number for these capacitors?
Are they all of one type or several ?
Many thanks.
Part # for Capacitors for Sys 9000 control head
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the "Repeater Builder" site has an article on spectra caps...
http://www.repeater-builder.com/motorol ... -caps.html
from the article:
>> Note that the A9 (sometimes called the System 9000) control head
>> uses different style capacitors and that control head does not suffer
>> this problem
I've had a couple of A9 displays go bad - one did exactly what you're saying, the whole display got gradually less bright. the other went from nice and bright, to no display at all overnight, with no dimming, bad segments, or other warning signs.
odss are, you just need to replace the display.
http://www.repeater-builder.com/motorol ... -caps.html
from the article:
>> Note that the A9 (sometimes called the System 9000) control head
>> uses different style capacitors and that control head does not suffer
>> this problem
I've had a couple of A9 displays go bad - one did exactly what you're saying, the whole display got gradually less bright. the other went from nice and bright, to no display at all overnight, with no dimming, bad segments, or other warning signs.
odss are, you just need to replace the display.
Yep, i second that.
I have yet to replace the caps in a X9K control head and have the display come back to full brightness.
The VFD, Vacuum Flourescent Display, tube in these control heads just dim with use over time. They are a vacuum tube, and like all vacuum tubes they age and grow dim. It's made worse by running the head at full brightness all the time, which is unfortunately the system default when turned on. When i had them i just made sure to tap the dim button at least once every time they were turned on. It will extend the life by not running them at full brightness.
If you have a service manual check voltages, if it all looks good then its just the display. If you don't and want to replace the caps go for it, but i doubt it will help, hasn't on any of the heads i worked on.
Last i checked the VFD was still available for something like $30 from Moto, but i would have to check MOL to see if they are still available now.
I have yet to replace the caps in a X9K control head and have the display come back to full brightness.
The VFD, Vacuum Flourescent Display, tube in these control heads just dim with use over time. They are a vacuum tube, and like all vacuum tubes they age and grow dim. It's made worse by running the head at full brightness all the time, which is unfortunately the system default when turned on. When i had them i just made sure to tap the dim button at least once every time they were turned on. It will extend the life by not running them at full brightness.
If you have a service manual check voltages, if it all looks good then its just the display. If you don't and want to replace the caps go for it, but i doubt it will help, hasn't on any of the heads i worked on.
Last i checked the VFD was still available for something like $30 from Moto, but i would have to check MOL to see if they are still available now.
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Many thanks for the help and the link.
I love that 11 character display and must admit that I run it on bright all the time during the day. I have about 6 stored Systems 9000 or A-9 heads which I began going through the other day prior to selling some equipment. I was disappointed to see that they were dim, though readable certainly at night.
Before the T35, D35--C9 (800mhz) Spectra market goes completely down the drain, I though I might sell most of mine.
I was about to order up a batch of capacitors so you guys saved me there. Oh, how I would have hated myself to have done all that work and still no improvement.
I haven't opened an A-9 head in a while though I've changed out many a button on many a head. It seemed like there was a lot of fancy soldering involved. Is that the case or is it more of a drop in board?
Thanks again.
I love that 11 character display and must admit that I run it on bright all the time during the day. I have about 6 stored Systems 9000 or A-9 heads which I began going through the other day prior to selling some equipment. I was disappointed to see that they were dim, though readable certainly at night.
Before the T35, D35--C9 (800mhz) Spectra market goes completely down the drain, I though I might sell most of mine.
I was about to order up a batch of capacitors so you guys saved me there. Oh, how I would have hated myself to have done all that work and still no improvement.
I haven't opened an A-9 head in a while though I've changed out many a button on many a head. It seemed like there was a lot of fancy soldering involved. Is that the case or is it more of a drop in board?
Thanks again.
-
kc7gr
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<smallsnip>Leadenwah wrote:Many thanks for the help and the link.
<bigsnip>
I was about to order up a batch of capacitors so you guys saved me there. Oh, how I would have hated myself to have done all that work and still no improvement.
FYI: You'll save a bundle on capacitors (and get better-quality parts) by not ordering from Motorola. I've been using the Panasonic 'HD' series parts in every Spectra I service, with excellent results.
Readily available from DigiKey, Mouser, and other distributors.
Happy hunting.
Bruce Lane, KC7GR
"Raf tras spintern. Raf tras spoit."
In the Spectra A9, 9000 series, control head there are only two capacitors that give problems. They are both 10uf at 50 volts, round alum. surface mount parts. They tend to leak and disturb circuits near them, or destroy the circuit traces and other parts near them.
I would recommend the replacement of both. Most BatBoarder's do not have the equipment for surface mount component rework, and I recommend using axial leaded parts for replacement.. much easier to work with.
The cap nearest the little transformer needs to be 10 uF at 50 volts and is the filter for the display voltage, the other one can be 10 uF at 25 volts. Both radial leaded parts.
I would recommend the replacement of both. Most BatBoarder's do not have the equipment for surface mount component rework, and I recommend using axial leaded parts for replacement.. much easier to work with.
The cap nearest the little transformer needs to be 10 uF at 50 volts and is the filter for the display voltage, the other one can be 10 uF at 25 volts. Both radial leaded parts.