Hello everyone, I am new to this forum and I need help. Amplifier that has been bothering me Crate TX30E (taxi): Crate TX30E Taxi Yellow Battery-Powered Amplifier
It's about 8 years old, working at 12V, the battery has been changed once, it is in a good condition. The output is TDA1560Q, this chip has two modes: B class and H class. Up to 10W - B up to 30W - H . It also has built in ELCO capacitors and circuitry for increasing the voltage so it can get more power with only at 12 V. Speaker is 8 ohms, two-way.
Problem: when output power exceeds 10-15 w it starts distorting until power does not fall under some 7-8 W, then it goes back to normal operation ..
I have replaced the TDA1560Q but it is still the same. I resoldered all suspicious connections and checked all the diodes. All the capacitors look OK, and visually there are no suspicious places. No way to determine where is the problem...😡
If anyone has advice please help me because I'm a bit desperate. I was refused at the repair shop because they didn't want to deal with amplifier worth 200-300 euros). Too cheap for them but not for me....
Any help is appreciated!
It's about 8 years old, working at 12V, the battery has been changed once, it is in a good condition. The output is TDA1560Q, this chip has two modes: B class and H class. Up to 10W - B up to 30W - H . It also has built in ELCO capacitors and circuitry for increasing the voltage so it can get more power with only at 12 V. Speaker is 8 ohms, two-way.
Problem: when output power exceeds 10-15 w it starts distorting until power does not fall under some 7-8 W, then it goes back to normal operation ..
I have replaced the TDA1560Q but it is still the same. I resoldered all suspicious connections and checked all the diodes. All the capacitors look OK, and visually there are no suspicious places. No way to determine where is the problem...😡
If anyone has advice please help me because I'm a bit desperate. I was refused at the repair shop because they didn't want to deal with amplifier worth 200-300 euros). Too cheap for them but not for me....
Any help is appreciated!
Peliminary search for schematic, - no go. Are you willing to try contacting Crate for the schematic? Give it a try and report back.
I just requested a schematic from LOUD(Crate)and will try to help as soon as I get it. I assume that you do not have a schematic as you didn't mention it.
Craig
Craig
Thanks for your effort, I don't have schematics... I just remmoved capacitors (largest - 4700 uF). They seem to be OK. (resistance more than 20 Mohm, capacity I cannot measure but they seem OK....
Pin 16 of the output chip is a mode select used for selecting between standby, mute, class B and class H. Is it receiving the right input?
Thank you for the schematics, I just woke up, I'll look into it now and make some measurements.
Equipment? acoustic guitar and mic that I made.
Equipment? acoustic guitar and mic that I made.
Thank you for the schematics, I just woke up, I'll look into it now and make some measurements.
Equipment? acoustic guitar and mic that I made.
Equipment? acoustic guitar and mic that I made.
Pin 16 is grounded according to schematic. I have acoustic guitar and mic that I made.I just wake up and I have to study schematic.. any tips?
No it's not. It's conneced to the +12V supply through a delaying RC circuit to acquire a startup mute feature. The voltage at pin 16 must rise above a certain level (refer to datasheet) in order for the chip to switch into class H operating mode. If it doesn't the output power is limited to that of the class-B mode (circa 10W).
Also, verify the condition of those 4700uF caps in between pins C1p - C1n and C2p - C2n. They supply the amp's high voltage rails during class H operation.
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sorry teemuk, you are right. I was looking at pin 12. Also sorry for multiple posts, my PC is crazy.
I'll look the voltage on pin 16 ...
I'll look the voltage on pin 16 ...
I just measured it:
Votage on pin 16 is 9,5 V on small power output
and 9 V when output voltage exceedes ~11 V RMS.
...almost no difference...
Votage on pin 16 is 9,5 V on small power output
and 9 V when output voltage exceedes ~11 V RMS.
...almost no difference...
I measured voltage over C37 and C35.
Without any signal the voltage is 10V on both of them.
But when output power increases, voltage drops on C 35 to 3-4 V.
Without any signal the voltage is 10V on both of them.
But when output power increases, voltage drops on C 35 to 3-4 V.
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JUst to double check some facts:
If amplifier has 30 W (8 ohm),
then I should be able to get 15.5 V RMS on the speaker, (sine wave, say 200 - 1000 HZ)
If amplifier has 30 W (8 ohm),
then I should be able to get 15.5 V RMS on the speaker, (sine wave, say 200 - 1000 HZ)
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