[Topaz305RK]

Need a little info please.

Have a Yaesu FT-990, no service manual. The light on the meter is dead.
Anyone ever change out one of these bulbs?
Is it a major undertaking or just minor surgery? Have changed a couple of
"grain of wheat" bulbs in dual band mobile radios before.
Just thought I would ask before tearing into the thing. If it is a real
major operation will send it off, other wise will dig in and do it myself.
Also, if someone has the service manual, perhaps you can pass along the part
number for the bulb, assuming it is a bulb and not a back lit meter of some
sort.

Sam - K7SAM

[Robert Kubichek]

Topaz305RK wrote:
Need a little info please.

Have a Yaesu FT-990, no service manual. The light on the meter is dead.
Anyone ever change out one of these bulbs?
Is it a major undertaking or just minor surgery? Have changed a couple of
"grain of wheat" bulbs in dual band mobile radios before.
Just thought I would ask before tearing into the thing. If it is a real
major operation will send it off, other wise will dig in and do it myself.
Also, if someone has the service manual, perhaps you can pass along the part
number for the bulb, assuming it is a bulb and not a back lit meter of some
sort.

Sam - K7SAM



It is a 12v lamp according to schematic,and you would be much better off
replacing it with a led and resistor...


Bob N9LVU

[Markus L]

Robert Kubichek wrote:
Topaz305RK wrote:
Need a little info please.

Have a Yaesu FT-990, no service manual. The light on the meter is
dead. Anyone ever change out one of these bulbs?
Is it a major undertaking or just minor surgery? Have changed a couple
of "grain of wheat" bulbs in dual band mobile radios before.
Just thought I would ask before tearing into the thing. If it is a
real major operation will send it off, other wise will dig in and do
it myself.
Also, if someone has the service manual, perhaps you can pass along
the part number for the bulb, assuming it is a bulb and not a back lit
meter of some sort.

Sam - K7SAM


It is a 12v lamp according to schematic,and you would be much better off
replacing it with a led and resistor...


Bob N9LVU

FT-990 "Technical Supplement":

Exploded View (Front Panel Assembly):
Meter Lamp 14V 150mA, Q1000075. If I interpret the drawing correctly,
the meter lamp goes into fuse holder P2000003.

Pilot Lamp Replacement:
Disconnect all cables, remove top and bottom covers.
Remove 7 screws from the edges of the front panel (2 bottom, 3 top, 1
upper left, 1 upper right).
Loosen 2 remaining screws at the lower edge on each side.
Fold front panel forward and down to access the inside.
Remove 2 screws in the lamp reflector.
Remove reflector to access lamp within.

Hope this helps!

73, Markus HB9BRJ / AE6MG

[Topaz305RK]

"Markus L" wrote in message
. ..
Robert Kubichek wrote:
Topaz305RK wrote:
Need a little info please.

Have a Yaesu FT-990, no service manual. The light on the meter is dead.
Anyone ever change out one of these bulbs?
Is it a major undertaking or just minor surgery? Have changed a couple
of "grain of wheat" bulbs in dual band mobile radios before.
Just thought I would ask before tearing into the thing. If it is a real
major operation will send it off, other wise will dig in and do it
myself.
Also, if someone has the service manual, perhaps you can pass along the
part number for the bulb, assuming it is a bulb and not a back lit meter
of some sort.

Sam - K7SAM


It is a 12v lamp according to schematic,and you would be much better off
replacing it with a led and resistor...


Bob N9LVU

FT-990 "Technical Supplement":

Exploded View (Front Panel Assembly):
Meter Lamp 14V 150mA, Q1000075. If I interpret the drawing correctly, the
meter lamp goes into fuse holder P2000003.

Pilot Lamp Replacement:
Disconnect all cables, remove top and bottom covers.
Remove 7 screws from the edges of the front panel (2 bottom, 3 top, 1
upper left, 1 upper right).
Loosen 2 remaining screws at the lower edge on each side.
Fold front panel forward and down to access the inside.
Remove 2 screws in the lamp reflector.
Remove reflector to access lamp within.

Hope this helps!

73, Markus HB9BRJ / AE6MG

Markus -

Think that was just the info I was looking for.
Thanks a bunch, very much appreciated.

Sam - K7SAM

[Bryan]

Robert Kubichek wrote:
Topaz305RK wrote:
Need a little info please.

Have a Yaesu FT-990, no service manual. The light on the meter is dead.
Anyone ever change out one of these bulbs?
Is it a major undertaking or just minor surgery? Have changed a couple
of
"grain of wheat" bulbs in dual band mobile radios before.
Just thought I would ask before tearing into the thing. If it is a real
major operation will send it off, other wise will dig in and do it
myself.
Also, if someone has the service manual, perhaps you can pass along the
part
number for the bulb, assuming it is a bulb and not a back lit meter of
some
sort.

Sam - K7SAM



It is a 12v lamp according to schematic,and you would be much better off
replacing it with a led and resistor...


Bob N9LVU

LEDs tend to have a very narrow dispersion angle. A friend (service
'mangler' for a pro-sound company) gave me a tip: file-off the lens of the
LED.
If you want to stay with grain-of-wheat bulbs, and can't get the OEM units,
you can find them at well-stocked hobby stores. To make them last longer,
you can use a constant-current source (LM317L, etc) to limit the in-rush
current. You'll lose 1.21V across the '317, which may still be acceptable.
73,
Bryan WA7PRC