Adcom GFA-5500 2-Channel Amplifier - Answered Questions & Fixed issues

well i can help you . tell me the wire color

Things to check: 1. With your multi meter, measure from left ground to right ground. What do you get? Measure from each input ground to chassis. What do you get there. 2. Get or make a pair of shorting plugs. Plug those into the inputs. Power on. Hum there or gone? 3. Turn the pre-amp on. Connect. Level of hum change with preamp on? 4 additional information. How efficient are your speakers? This is a big amp, high-efficiency speakers may show some noise, while low-efficiency speakers won't. A trip back to the shop may be indicated, too.

we don't sell fuses here, bro....

not unless it has a Bridge switch OR you design an inverter circuit for one of the inputs. If it has XLR inputs you can try to invert pins 2 & 3 on one of them, that might work...

The colour code or the value it states on R23 should give you the reading you will see on a test meter on the Ohm setting. If the value doesn't match the colour code of the resistor then you should replace it. It's best to take any resistor out of the circuit to test as strange readings can be caused in circuit. The same applies to the left channel one. Ohm meters are not expensive if you don't have one and can be got from various places that sell electronics parts etc. Some car part dealers sell them. They are a worthwhile investment and can be used for many types of problem.
It's likely that it's a basis resistor and failed when the power jobs went.

If you're friendly about it , the folks at ADCOM will probably give you a schematic
Call and talk to tech support

I's not a fuse, if it would have been one the entire amp would have been dead or severely affected. It can't be a bad connection, the warning light lights only when the input signal goes beyond a certain limit and forces the amplifier over it rate power.
If you see the warning light even without no input connections then something is wrong with the protection circuit - strangely it has failed before the amplifier it was suppose to protect. Since this is very unusual failure you should send it to be repaired at the dealer.

go to radio shack near you and change the fuse with the same rate-------or any electronics store near you.

What I would do is look around inside and see if anything is burnt or broken, pay close attention to the heat sink area.
With neither channel working you have something that's common to both channels that is causing the trouble.
You should be able to see any fuse by looking inside, they might be covered up, but should be easy to get to.

Any fuse blowing is caused by a shorted component in either the power supply section or main audio amp part. Follow the fuse circuit and see where it leads you. Look around for burnt of damaged parts. Suspect anything sitting on a heat sink. The most common culprit is the audio amp main transistors, especially if someone shorted the speaker leads together. In the power part it could be the transformer, the large Electrolytic capacitors, rectifier, or voltage regulator. Some amps use an IC for amplification and this can blow the fuse.

If the noise goes away when you turn down the volume, it means that it starts before the volume control. And if the volume control has no effect then it is the stage after the control.
Transistors, IC's, bias resistors or ceramic capacitors can cause noise.
If you heat up a transistor by touching it with an soldering iron, it might cause the problem to start up. If it does you have found the culprit. You can also try spraying them with Servisol freezer spray which can be got from Maplin UK or Radio Shack USA. This will cool down any part and help detect the faulty ones.

Adcom makes a great amplifer! Usually broken highs and no bass means blown speaker. Try hooking it up to a completely different input source. Try different speakers also. If problem persists, check the fuse. Most will have a fuse on the back you can screw out. Some have two fuses (one for each channel) If this doesn't fix the problem it could be expensive to fix. Also, does this model ave the thermal protection light and if so, does it come on at all?

Did you check the fuses in side the amp?

If your Adcom GTP-450 preamp is only working through an external processor, there could be several potential reasons for this issue. Here are some troubleshooting steps you can take to try to identify and resolve the issue:

1. Check Input Selection: Ensure that you have selected the correct input source on the preamp. Sometimes, if the incorrect input is selected, it may seem like the preamp is not working.
2. Inspect Cables and Connections:
   • Make sure that all cables (audio, video, power) are securely connected to both the preamp and the external processor.
   • Check for any loose or damaged cables. If you find any, replace them.
3. Verify the External Processor's Settings:
   • If you are using an external processor, ensure that it is set up correctly and functioning properly. Check its input and output settings.
4. Check for Mute or Volume Levels:
   • Verify that the preamp's volume is not set to zero or muted. Also, check the volume settings on the external processor.
5. Test Different Inputs and Outputs:
   • Try using different input and output connections on both the preamp and the external processor to see if there is any change in behavior.
6. Reset to Factory Defaults:
   • Consult the user manual to see if there is a way to perform a factory reset on the preamp. This can sometimes resolve software or configuration-related issues.
7. Firmware or Software Update:
   • Check if there are any available firmware or software updates for the Adcom GTP-450 preamp. Updating the firmware/software can sometimes address compatibility or performance issues.
8. Consult the User Manual or Manufacturer's Support:
   • Review the user manual for troubleshooting tips specific to your model. If the issue persists, consider reaching out to Adcom's customer support for further assistance.
9. Consider Professional Repair:
   • If none of the above steps resolve the issue, it may be a hardware problem. In this case, consider seeking help from a qualified audio technician or contacting Adcom for repair options.

Please be cautious when performing any troubleshooting steps, especially if they involve opening or modifying electronic equipment. If you're unsure about any step, it's best to seek professional advice to avoid potential damage.

There are several things that could be causing the lack of sound output from your Adcom GFP 710. Here are a few things to check:

1. Check the cables: Make sure that the cables connecting the preamp to the power amp and speakers are securely plugged in and in good condition.
2. Check the input selection: Make sure that the correct input is selected on the preamp.
3. Check the volume: Make sure that the volume is turned up and not muted.
4. Check the balance: Make sure that the balance is set correctly and not all the way to one side.
5. Check the output jacks: Make sure that the output jacks on the preamp are functioning properly.
6. Check the power supply: Make sure that the power supply is providing the correct voltage to the preamp.

If none of these solutions work, it is possible that there is an issue with the preamp itself. It may need to be serviced or repaired by a qualified technician.

Thanks for your suggestions. However I am using carefully boxed clean CDs and the skipping is on all. The Laser glass is clean. Since submitting the problem I removed case and the CD is lifted off tray by a lift motor which has a round nylon top on the shaft which "sandwiches" the CD against a freely rotating plastic piece in a lipped cylinder container. The lift motor then rotates the CD which is read by a separate fixed laser. My current suspicion is that the CD is slipping inside the rotating "sandwich". Hopefully someone who has worked on an Adcom GCD 600 can suggest a fix.

Back in the late 1980's the GCD-575 was about as good as you could get in CD players. Today it likely can still hold its own when rejuvenated to original operating condition when it left the factory (but can't play SACD's hires layer). Main problem... deteriorated main board soldering, a few hours with a solder sucker, (best to resolder use 2% or 4% silver solder everywhere) and replace 32 year old caps, and this set should equal the sound of a mega-buck player (also change the open/close belt). Modern caps are likely smaller so a 2,200 can be replaced by a 3,300 or 4,700 uF. part at the same voltage, etc. the output cap value should be doubled, and a bipolar used, or bypassed with a polypropylene or Teflon, IIRC plenty of room is available inside the case for either (or both). That is a lot of work. Well worth it. -Steven

https://www.diyaudio.com/forums/solid-state/236765-adcom-gfa-555-ii-blowing-main-line-fuse-ideas.html

Hello Curtis, comment that teams accompany the Adcom, to know where the signal arrives at the entrances of the GFA6000, I ask you this, to make a map of your sound system and try to find the possible place of failure Try the left and right speakers, in the outputs that work, it can be the Surround, to check that they are working I await your comment Greetings Franco Dosil Hola Curtis, comenta que equipos acompa?an al Adcom, para saber de donde llega la se?al a las entradas del GFA6000, te pido esto, para hacer un mapa de tu sistema de sonido y tratar de encontrar el posible lugar de falla Prueba los parlantes izquierdo y derecho, en las salidas que funcionen, puede ser las de Surround, para comprobar que est?n funcionando Espero tu comentario Saludos Franco Dosil

Check and download from service manual.com the operation manual.