tuning indicator lamp replacement, Onkyo TX-2500

[brillcat]

I'm into the guts of my first vintage clean-up, a TX-2500. A cool guy at the local stereo repair has given me some great tips and I followed DeOxit for Dummies which I read somewhere here, all good stuff... and I have not broken anything yet but there is still time

It needs 3 lamps which dwojo is selling me. Not to concerned about replacing 2 indicator lamps but man, trying to figure out how to replace the tuning needle lamp is a struggle. The lamp housing looks so fragile, I am afraid I'd destroy it just trying to open it up. Has anyone done this before on a 2500 and/or have some tips? Thanks in advance!

 

[westend]

I looked through the service manual and there are lots of procedures for aligning the tuning indicator if it is removed. You either have the quarrtz lock or servo lock model. Do you know if the tuning indicator lamp goes off and on when the tuning circuit locks or is there a separate indicator lamp for tuning lock. The vintage knob page also states that the tuning knob is touch actuated to delock the tuning circuit and, once untouched, does its locking thing. It is a fairly sophisticated locking circuit so you would need to know if the indicator lamp is connected to this circuit.

 

[brillcat]

Hmmm, great questions. This is a servo model, and the only indicator light that presently works at all is "Stereo." I presumed the "Tuned" and "Locked" bulbs were burned out, but maybe there's something else going on?

 

[westend]

Chances are the bulbs are out but I don't know enough about that receiver to venture a guess. IIRC, from the service manual, nearly all five of the dial bulbs were fuse lamps and there was one of a different rating. Do you have the service manual? If not, it is available here. You will need to register to DL it. It's painless.

 

[terra1]

Maybe show a picture.

Some needle pointers have metal tabs that need to be pried up to remove a rubber pad to access and remove the bulb. A careful steady hand and patience is required, but you should be able to open it without snapping off the tabs if that is what you are concerned with. Sometimes there may be glue or other tabs holding the bulb or string down but you can always reposition the pointer if you happen to accidentally dislodge it.

If the stereo light works that's a good sign. At least you have stereo!

Does the signal strength and tuning meter seem to work and lock into optimal position when you let go of the tuning knob even when you are slightly off center on the tuning meter? That would indicate the tuned and locked mechanisms are still working but just the bulbs burnt out. On my Onkyo T-9 tuner, there is also a switch in the back to adjust the sensitivity of the touch sensor.

If it is awkward getting to the pointer because it is obscured under the ledge of the faceplate, you may need to remove the face plate to get better access.

 

[brillcat]

I found that if I remove the faceplate and another backet behind it (that the pointer slides along) the pointer can be brought forward for easier access. But since it is attached to the tuning string, I'll have to remove the string to bring it forward far enough to get to the bulb. I'll take lots of pics first and I've downloaded the manual (tnx westend)... I have to travel this week so it looks like it will be a good project next weekend!

 

[sregor]

2 comments about the servolock. The touch sensor is done by amplifying the 60 hz buss when you touch the control. Sometimes a cleaning is all it needs. Also, there is on some Onkyo's (not sure if it applies here) a sensitivity control on the back panel for the touch sensing. YMMV

 

[brillcat]

Success! I got the right lamp (actually several) from Dwojo and after some careful trimming of glue holding the leads to the tuning silder, I was able to bring the leads forward several inches -- enough to solder the wires to the leads of the new lamp. Now with all the various lamps replaced everything works great. The tuning needle still lines right up on the correct frequency and the servo lock is doing its thing too. Thanks everyone for your ideas and support.