Just registered. Before doing so I read all 115 pages of this forum looking for a solution for the very bad FM-sound quality in my 2002 GS300.
Found a posting from Justin Crocket and mailed him but no answer.
So, here's a quote from a specific post on this problem:
QUOTE
Firstly, do you have experience of surface-mount technology? If not I suggest you don't touch the radio.
Secondly, do you know how to remove the radio from the dash? Again if you are not sure seek professional advice.
Now that that's over I've attached two drawings from the Pioneer manual.
The two capacitors to remove are C101 and C102 on the Tuner PC board. both are of 0.056mfd and are chip capacitors that shunt the junctions of R101/102 and Q101 and Q102 to earth.
They are fairly easy to locate, just follow pins 25 and 26 from connector U21 (in the middle of the board layout) through R101 and R102 and the two capacitors shunt signal to ground on the base of Q101 and Q102.
This is a totally unofficial modification, you carry it out at your risk.
Roughly the time constant of 2.2K ohms and .056mfd is: 123 microseconds, the correct UK FM de-emphasis time constant should be 50 microseconds, however this is already accomplished by C151/R151 and C152/R152 on the Tuner PCB (3.3K and .018mfd = 59 microseconds minus a bit for source impedance is probably 50 microseconds)
I reckon they mis-specified C101/102 they should be more like 560pf
Secondly, do you know how to remove the radio from the dash? Again if you are not sure seek professional advice.
Now that that's over I've attached two drawings from the Pioneer manual.
The two capacitors to remove are C101 and C102 on the Tuner PC board. both are of 0.056mfd and are chip capacitors that shunt the junctions of R101/102 and Q101 and Q102 to earth.
They are fairly easy to locate, just follow pins 25 and 26 from connector U21 (in the middle of the board layout) through R101 and R102 and the two capacitors shunt signal to ground on the base of Q101 and Q102.
This is a totally unofficial modification, you carry it out at your risk.
Roughly the time constant of 2.2K ohms and .056mfd is: 123 microseconds, the correct UK FM de-emphasis time constant should be 50 microseconds, however this is already accomplished by C151/R151 and C152/R152 on the Tuner PCB (3.3K and .018mfd = 59 microseconds minus a bit for source impedance is probably 50 microseconds)
I reckon they mis-specified C101/102 they should be more like 560pf
Now, as Justin might not be on this forum anymore:
Anybody can help me in getting those schematics and picture?
Would be very greatfull!
Thanks in advance.