I have an Adcom GFA 555 with a damaged input section. I have a 555 service manual but the front end circuit board (A020 A) and related parts list don't match. I understand two different boards were used for the 555 (not counting the 555II). If anyone has information one the other configuration (my board says S394V-0) I would greatly appreciate it.
555 bias adjustment
I don't have an answer to your question, but I do have a 555 that I could take a look at for you. I am looking for the test points and bias voltages called out for the 555, but do not have the service manual. Does your manual cover this? I will go check the p/n of my board and report back
Bill
I don't have an answer to your question, but I do have a 555 that I could take a look at for you. I am looking for the test points and bias voltages called out for the 555, but do not have the service manual. Does your manual cover this? I will go check the p/n of my board and report back
Bill
Do either of you know what the vac is coming out of the trans former. Also could you tell me the vdc on the caps.
I have the 555 manual via PDF if you need it.
Ben
I have the 555 manual via PDF if you need it.
Ben
According to http://www.diyaudio.com/forums/showthread.php?postid=1423844#post1423844ben62670 said:
VAC is 52-0-52, and VDC unloaded is 75.
Tranformer Primary Voltage = 122.9
Secondary Voltage = 121.8
DC Votage Across Capacitor 81.2
No input signal idle
Secondary Voltage = 121.8
DC Votage Across Capacitor 81.2
No input signal idle
adcom gfa 555 service manual request
Help me, I need of ADCOM GFA-555 , full service manual in PDF they can send me?
Thank you. Roberto
ben62670 said:
Help me, I need of ADCOM GFA-555 , full service manual in PDF they can send me?
Thank you. Roberto
Manual for GFP 555
Post your email address and I will email you the manual. I can't get your email from your registration.
Bill
Post your email address and I will email you the manual. I can't get your email from your registration.
Bill
manual request
Yes , you can send service manual for adcom gfa 555, at may email:
blobbulobis@inwind.it
Kindly Roberto
Yes , you can send service manual for adcom gfa 555, at may email:
blobbulobis@inwind.it
Kindly Roberto
IIRC:
Trafo VAC on the 555ii was 60-0-60. Caps were 100vdc.
The original 555 might be 57-0-57 if not 60-0-60, caps same 100vdc.
Trafo VAC on the 555ii was 60-0-60. Caps were 100vdc.
The original 555 might be 57-0-57 if not 60-0-60, caps same 100vdc.
Anyone still got the manual
Hi i have a GFA-555 from adcom that doesn't turn off, ive checked the switch and its bad. i replaced it and still same problem. so i need the service manual if anyone still has it my email is dog5cd@yahoo.com.
Thank you
Hi i have a GFA-555 from adcom that doesn't turn off, ive checked the switch and its bad. i replaced it and still same problem. so i need the service manual if anyone still has it my email is dog5cd@yahoo.com.
Thank you
Send an email to Adcom and they'll email the manual to you. Just received a 545 manual from them.
Craig
Craig
Re: Anyone still got the manual
This is a common failure, due to lack of mains surge limiting (ie slo start). I modded mine here on DIYaudio.
gooshpoo said:
This is a common failure, due to lack of mains surge limiting (ie slo start). I modded mine here on DIYaudio.
Doesn't look like this is the case any longer. I emailed Adcom yesterday to get a couple service manuals via email, but they wrote back that the service manuals cost $19.95 each. 😛 Is this a "bad economy" thing?
Okay, replying to my own post, but...
I emailed Adcom and asked about their apparently new charge for service manuals. Adcom stated that the charge was implemented in March 2009. So it looks like they won't be the source for any free service manuals going forward. They do provide owners manuals free through their website, though.
I emailed Adcom and asked about their apparently new charge for service manuals. Adcom stated that the charge was implemented in March 2009. So it looks like they won't be the source for any free service manuals going forward. They do provide owners manuals free through their website, though.
I have a adcom gfa 555 ii which i recently got, the amp is mint in condition and runs perfect. However, the amp gets quite hot from the top right corner near the heat sink whereas, the right side of the amp runs cool (or gets warm not hot as the right side). Is this normal or means that there is something worng inside and i need to get it checked before something goes wrong?? please help
Well, there are several possibilities.
Just a couple of the more likely ones.
1. Check the bias of each channel . Are they comparable (within 20%). The service manual outlines the procedure and identifies the test points. You will need and volt meter and a power resistor.
2. Have you reconfigured you system recently? It is possible you now have something oscillating? You would not necessarilu hear it, but it would show up on a scope.
BTW, these are great amps and very good deal at their price point. However, they are getting older and probably desrve some TLC (replacing the electrolytic caps, some bypass caps, etc.)
Just a couple of the more likely ones.
1. Check the bias of each channel . Are they comparable (within 20%). The service manual outlines the procedure and identifies the test points. You will need and volt meter and a power resistor.
2. Have you reconfigured you system recently? It is possible you now have something oscillating? You would not necessarilu hear it, but it would show up on a scope.
BTW, these are great amps and very good deal at their price point. However, they are getting older and probably desrve some TLC (replacing the electrolytic caps, some bypass caps, etc.)
thanks for the info. Unfortunately i dont have the user manual for this amp. Is it possible if you can email it to me and also let me know which section of the manual you are referring to in point 1. you can mail me on faysalusman@msn.com
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