Laney TT50H No Outout

[ca7922303]

This pic is from post # 466 a couple days ago. Where does the black wire at the top of the picture go?

Chassis ground and back to board(photo)

[g1]

No presence or damping function. Low distorted output,

This pic is from post # 466 a couple days ago. Where does the black wire at the top of the picture go?

[g1]

Measure DC volts at both sides of R34, and both sides of R44.

[ca7922303]

That's all good now and ready to test. I don't know your level of experience as far as amp usage, so I will say that 'presence' control is not as obvious as other tone controls. It just puts some sparkle or brightness into the upper midrange frequencies. Probably most noticeable with overdriven tones which are rich in harmonics.

If presence works backwards, or there is loud squeal right when you turn it on, you will need to swap the green and blue wires at the lugs marked 'grids'.

No presence or damping function. Low distorted output, oscillation only on channel 3 when boost or xpand is engaged.
Swapped grid wires, oscillation on channel 2 & channel 3 but if either boost or xpand are engaged , oscillation stops, but low distorted output seems the same

[g1]

That's all good now and ready to test. I don't know your level of experience as far as amp usage, so I will say that 'presence' control is not as obvious as other tone controls. It just puts some sparkle or brightness into the upper midrange frequencies. Probably most noticeable with overdriven tones which are rich in harmonics.

If presence works backwards, or there is loud squeal right when you turn it on, you will need to swap the green and blue wires at the lugs marked 'grids'.

[ca7922303]

I guess you mean you restored the jumper and it now measures 0 ohms between the solder joints it connects to?



Those other values are for resistors on the preamp board. These ones are on the main board, pg.10 of the service manual pdf (lower left area of schematic).

Now with R44 re-installed, check resistance again at the R45 solder joints.

R45(4.5k ohms).

[ca7922303]

I guess you mean you restored the jumper and it now measures 0 ohms between the solder joints it connects to?



Those other values are for resistors on the preamp board. These ones are on the main board, pg.10 of the service manual pdf (lower left area of schematic).

Now with R44 re-installed, check resistance again at the R45 solder joints.

I'll get to it this evening, at work now. Thanks.

[ca7922303]

Also, I see now on schematic that R34/R44 are correct. Thanks

[ca7922303]

I guess you mean you restored the jumper and it now measures 0 ohms between the solder joints it connects to?



Those other values are for resistors on the preamp board. These ones are on the main board, pg.10 of the service manual pdf (lower left area of schematic).

Now with R44 re-installed, check resistance again at the R45 solder joints.

That is correct, zero ohms between the solder joints it connects to.

[g1]

Trace repair jumper solder joints(0.0 ohms)

I guess you mean you restored the jumper and it now measures 0 ohms between the solder joints it connects to?

Reinstalled R44(4.5k ohms) schematic shows(22k)
R34(10k ohms) schematic shows (100k)

Those other values are for resistors on the preamp board. These ones are on the main board, pg.10 of the service manual pdf (lower left area of schematic).

Now with R44 re-installed, check resistance again at the R45 solder joints.

[ca7922303]

It looks like the leg of R45 is coming through from the other side, which it should. The 2 yellow arrows below show the 2 ends of R45 (mounted on the component side of board). You should measure around 100K between the 2 yellow arrows. If not you will need to replace R45.
If it measures good, re-install the jumper and measure between the pads of R44 (with R44 still removed). That should also measure around 100K when jumper installed.
Will be back tomorrow.

Reinstalled R44(4.5k ohms) schematic shows(22k)
R34(10k ohms) schematic shows (100k)

[ca7922303]

It looks like the leg of R45 is coming through from the other side, which it should. The 2 yellow arrows below show the 2 ends of R45 (mounted on the component side of board). You should measure around 100K between the 2 yellow arrows. If not you will need to replace R45.
If it measures good, re-install the jumper and measure between the pads of R44 (with R44 still removed). That should also measure around 100K when jumper installed.
Will be back tomorrow.

R45(99.6k ohms)
R44 pads(99.6k ohms)
Trace repair jumper solder joints(0.0 ohms)

[g1]

Trace jumper removed

It looks like the leg of R45 is coming through from the other side, which it should. The 2 yellow arrows below show the 2 ends of R45 (mounted on the component side of board). You should measure around 100K between the 2 yellow arrows. If not you will need to replace R45.
If it measures good, re-install the jumper and measure between the pads of R44 (with R44 still removed). That should also measure around 100K when jumper installed.
Will be back tomorrow.

[ca7922303]

Just remove that jumper and try to clean the solder off those solder pads, but without pushing out the leads of the components that are mounted on the other side. Post a picture.

Trace jumper removed

[g1]

Be off work shortly, can probably remove some of the solder and get correct reading.

Just remove that jumper and try to clean the solder off those solder pads, but without pushing out the leads of the components that are mounted on the other side. Post a picture.