Sony hIFI AMPLIFIER  - Page 1
Forum section: electronics / general

author: Dennis lowey
author_rank: Newbie
timestamp: January 18, 2018, 03:51:23 pm
content: My amp doesn't make the usual click after I turn it on. Help anyone

author: Zero999
author_rank: Super Contributor
timestamp: January 18, 2018, 03:56:54 pm
content: Quote from: Dennis lowey on January 18, 2018, 03:51:23 pmPlease provide more information.

author: Zucca
author_rank: Unknown
timestamp: January 18, 2018, 04:00:20 pm
content: A remarkable suggestion: bring it to an amp repair shop.Some other "little" suggestions...0) High voltage can kill you, are you not afraid?1) Why not use a screwdriver and open it up?2) Go to Repair Section and post picutres, details, measurements and further findings.3) High voltage can kill you, are you not afraid?4) High voltage can kill you, are you not afraid?Z

author: Dennis lowey
author_rank: Newbie
timestamp: January 18, 2018, 04:08:06 pm
content: Well normally when i turn on the amp the power comes on then a couple seconds later I hear a click and the music starts. Well now the power comes on but it doesn't click on. The lights come on but it doesn't make the click any more or play musi

author: Zero999
author_rank: Super Contributor
timestamp: January 18, 2018, 04:09:34 pm
content: Posting the model number, age and a few pictures would help.

author: Dennis lowey
author_rank: Newbie
timestamp: January 18, 2018, 04:17:59 pm
content: Model no str vx350 and picturs in a min. As well I dont know how old

author: Dennis lowey
author_rank: Newbie
timestamp: January 18, 2018, 05:00:09 pm
content: Pics

author: james_s
author_rank: Super Contributor
timestamp: January 18, 2018, 07:49:38 pm
content: I'm not familiar with that particular amplifier but some of them have a protection circuit that will not activate the speakers if it detects a fault. Without any information I would suggest checking for shorted output transistors. If you are not familiar with the operation and troubleshooting of audio amplifiers you're probably going to have to find someone who knows what they're doing to look at it. Amplifiers are not trivial to repair, if not done right you can easily blow up your expensive new parts instantly when you power it on.

author: IanMacdonald
author_rank: Frequent Contributor
timestamp: January 18, 2018, 08:40:58 pm
content: This uses an 'STK' output module, and the click is almost certainly a speaker protection relay. The relay will not close if there is DC on either output pin of the STK. (If it did, your speakers would be fried)Faultfinding should be donewithoutspeakers connected. Check the supply voltages are all present, and check the output pins of the STK. There should be less than about 0.5vDC on them.There is also what looks like an aux supply regulator near the front panel on a small heatsink, which looks like it's been running hot. Another item to check. The relay may be powered from this, so..A missing (positive or negative) DC supply rail could cause the problem, but if they are present and correct then likely the STK has failed. These modules are awfully sensitive to output shorts, and even a loose whisker of wire on the speaker binding posts can blow them in milliseconds.Changing the STK is not a tremendously difficult soldering job, a cheap spring desolder pump will be adequate top get the old one out.As always on amplifiers be aware that the two big electrolytics for the + and - output stage supplies can hold charge for some considerable time, so discharge them with a resistor before soldering or whatever.Also when working on any mains gear,unplugthe supply. Do not rely on the panel switch, which might be faulty.HTH.

author: james_s
author_rank: Super Contributor
timestamp: January 18, 2018, 10:14:12 pm
content: I never did care for those STK hybrid modules. They seem to be somewhat fragile, and replacements tend to be difficult to find and expensive. Most of the time with an amp that uses them if it has a fault like this the STK module is bad.

author: cvanc
author_rank: Frequent Contributor
timestamp: January 18, 2018, 11:52:04 pm
content: Quote from: james_s on January 18, 2018, 10:14:12 pm^^^What he said.^^^Plus, almost every "STK" module sold these days is a counterfeit.

author: NiHaoMike
author_rank: Super Contributor
timestamp: January 19, 2018, 05:07:59 am
content: Maybe there's a market for adapter PCBs that adapt a modern amplifier chip to where the old module went?