|
|
|
|
|
|
|
|
|
|
|
|
10-08-00
Q: I am curious to know the difference between the US version of the Marantz
2385 and the European 2385. I am in possession of a black Marantz 2385
European model. I looked at the service manual for the unit and it indicates
that the power output at 8 ohms is 200 watts as opposed to the US version of
185 watts per channel. Any information would be appreciated.Thanks
A: Hello,
There are differences in the way the power output is measured. The European standard lists power output at 1% distortion, the U.S. does not. The European rated power distortion spec. is measured at 1kHz, the U.S. spec is measured across the band. The U.S. spec. specifies that both channels are driven at the same time, the European spec. does not. All of these factors will lead to a higher output rating.
Thanks for writing.
09-15-00
Q: Hello,
I own a Sherwood S-8900 receiver. When I turn the power on I get a loud
pop from my speakers. This happens even with no inputs selected, and if
I turn on the unit with the speaker selection button off, it pops the
second I push that button.I was told there was a relay to prevent this and it may be stuck. Well
I can find no such relay.(It should be clear right?). Someone also
suggested that there might be a capacitor wired at the back of the
volume pot. And it could have dried up. No such luck either. Do you have
any ideas? ThanksBuzz
A: Hello Buzz,
What I believe you have here is DC on your speaker outputs. Take a DC volt meter and measure accross the speaker outputs, first the left, then the right. You should have a reading of zero, plus or minus a couple of hundred millivolts. If you have more than that, which I'm sure you do, then you may have a component failure. If you're lucky, the amp has a DC offset adjustment that needs to be tweeked. Your S-8900 was made in the early seventies (1973-1974) and may have preceeded the 'protect' relay design.
Thanks for writing.
Tim
09-11-00
Q: Tim,
Where can I find parts for a Sansui A-505 amp? It died. I checked the fuse
but it keeps blowing. Normally I would try a power xsistor but it appears
to be some sort of integrated component or op amp??? I tried Newark and
they never heard of the part # from the component.Any help would be greatly appreciated.
Dave
A: Hello Dave,
I do not have any info on that model, but, it sounds like you have an integrated output section. This is basically a giant IC that contains all of the components in the amp section that previously could be replaced individually. The good news is that these should still be available, the bad news is that its going to cost you. There should be a number on the IC that will cross to an STK-XXXX. If there is no number that you can cross reference, then you are at the mercy of Sansui for that information. The problem could also be a problem in the power supply, but not as likely as the giant IC from hell. Good luck and thanks for writing.
Tim
Thanks for replying. The part #s on the amp are 4843ED68 (the 6 may be a
C) and STK4843 (Stereo Amplifier). I tried Newark and other places and they
couldn't x-ref it. Any suggestions?Dave,
The STK-4843 is the key. I was not able to cross it either. You may want to contact older service centers and see if they have any NOS (new old stock). Otherwise you are SOL (sh%$ out of luck). I understand that some of the old STK series integrated circuits have been discontinued. This is one of many reasons that I am vehemently against this type of design. Please let me know if you find a source.
Tim
08-30-00
Q:Dear Tim,
Several years ago I loaned this amp to a friend to use at her wedding. It
came back smelling of smoke, and no longer functioning. I was told that
"someone" had touched the two speaker leads together and it "just quit
working".I have saved it in hope of finding someone who could help me bring it back
to life. One of the EE's I work with said he would tackle the problem, but
needed a schematic. I tried Sansui who sent me to High Value. They sold me a
schematic for an A-1000. The EE says it is not the same amp (wrong
schematic).Your on-line answers look like to are willing to help the average Joe, so
I'm hoping you can help me.Here are my questions; What is this unit worth/ is it worth spending a few
dollars on? If yes, where might I get a schematic? To date, I have bought
replacements for the parts that looked scorched (NTE 374,373,36,37,2362 and
2361). Can you pass on any troubleshooting information or things to pay
close attention to?I would greatly appreciate any help you could provide.
Thank you and please keep up the good work.
Sincerely,
Ken Fender
A:Hello Ken,
Your A-1000 was made between 1989 and 1990, it retailed for $200.00 and is rated at 30 watts per channel. This was an inexpensive amp and it's used value is certainly less than $100.00. I can offer no help in locating a schematic. If you decide to get it fixed, be sure and power it up using a variac following component replacement and monitor the current draw. Otherwise you stand a good chance of losing all of your replacement parts.
Thanks for writing.
Tim
08-16-20
Q:Hi Tim,
I've got a Marantz 2275 with intermittent selector & tone mode switch
problems that I believe to be the result of dirty contacts.
I'd like to spray the contacts with a cleaner but I'm not sure how to
disassemble the unit enough to gain access to the contacts. The biggest
problem I see is not knowing how to remove all the control knobs without
breaking them.
Can you help me?
Best regards,
CliveA:Hello Clive,
Getting inside these old Marantz units can be tricky. Make sure you have
stored up a considerable amount of patience before starting. The trick for
the knobs involves the use of two teaspoons. Place the spoons on opposite
sides of the offending knob with the round bottom side against the
faceplate. Then press evenly, and slowly, on the spoon handles and the
knob should budge. The use of the spoon prevents damage to the faceplate
because of the smooth, round surface. Using two of them allows you to
apply equal force in the direction of the knob shaft.Thanks for writing.
Tim
07-06-00
Q:Hi Tim,
Most receivers I find only tell you the watts that the receiver consumes written on the
back. can you divide this by number of speaker outputs to get the max watts per channel?
Thank You ! Brian...A:Hello Brian,
No, you can't. Sometimes that number includes the power used by the AC accessory jacks. Even if it does not, the amplifier is not 100% efficient. 100 watts of consumption will not give you 100 watts of output. The efficiency will vary by amplifier design, power supply design, etc. You might as well judge the power output by how much the unit weighs.
Thanks for writing.
Tim
06-05-00
Q:Hello Tim,
After reading through all the other letters I thought I'd try asking your
advice about my recently 'dead' Yamaha A-960 amplifier.
I bought this beauty back in 1980, hard to believe that twenty years have
gone by... Anyway, about the only trouble I ever had was the light inside
the on/off switch burned out during the first two months I owned it and then
once more about 1 and 1/2 years ago. Recently, after listening to some music
and then shutting the system down, it failed to turn back on later that day.
I could see that power was coming into the machine since the light for the
phono cartridge selector was showing me it's red light.
I thought my on/off light had once again burned out, but both a visual
inspection and a check with my multi-tester seemed to indicate the bulb is
in working order. Can you give me any advice about what I can look for
inside this amp, I'm not very comfortable with heavy duty electronics, but I
can use a multi-tester and follow a schematic(if I had one). Any tips on
troubleshooting the amp would be appreciated.Also, can you tell me where I
can get a schematic for this amp?
David
A:Hello David,Check the fuses and power supplies. I seem to recall that Yamaha made a component in that era that would not work if the power light was out. I don't know which model it was, but you should check the lamp out of circuit. Check with Yamaha for technical documentation.
Thanks for writing.
Tim
Tim,
Thanks for suggesting to check the power lamp out of the circuit...that was
indeed the problem. I've removed the bulb and just soldered a wire between
the two attach points on the circuit board and everything is now functioning
terrifically!!!
Thanks again,
David
05-30-00
Q: Tim,
I have a circa 1978 Pioneer CT-F9191 cassette deck. It has played well for
years but now the left channel has a constant hum (in place of the audio). I
cleaned the heads and that seem to fix it for a while (perhaps coincidence).
The problem is intermittent, some times it does it other times not...any
clues???A: Hello,
There is a giant switch inside the unit that switches in and out of the record and play modes. I would bet that if you switch between record and play a few times the problem will go away. Eventually, you may have to clean the switch. You can't miss it, it is operated by a giant solenoid. The other possibility is a bad connection on one of the head wires.
Thanks for writing.
Tim
03-25-00
Q: Mr. Whyte,
I came across a Pioneer SX-780 receiver at a garage sale a few months ago, and the nostalgic look really appealed to me. I began fumbling around trying to get the girl to show some signs of life, but only the panel lights came on; I could not coax it to recognize a source, whether external or from the tuner. I still felt that it was not a lost cause, and, after a little more deliberate tinkering, I led the seller to offer to give me the receiver and a newer Pioneer CT-50R tape deck. The deck did not work, either, but I determined that the problem was a stretched belt in the inertial drive of the transport mechanism. The receiver has given me a bit more trouble. I pulled the wood case and the sheet metal bottom plate off of the unit when I got home, and examined the workings for any obvious problems. Finding none, I connected a portable CD player via the auxiliary input ports and was able to get a source indication and sound through the headphones. The tuner produced nothing until I dusted it off, rotated the fuses in the panel on the bottom of the receiver (this may have cleaned the contacts, but I may just be fooling myself), and attached an adequate antenna. At this point, output was clear and strong, and the receiver easily drove a pair of speakers. I buttoned everything up and set the receiver up in my room, where it served faithfully for about 3 months. I noted that every time I flipped the power toggle to turn the unit on, the source indication would light and there would be silence for several seconds, then there would be a loud click (apparently from a relay I located on the main PCB) followed by normal operation. I left the stereo running at low volume as I went to sleep one night, and when I awoke, the panel was still lit, but there was no source and no sound. Despite the application of all techniques I had used when I acquired the receiver, I could not revive it. It lay on the floor, covers removed, for over 2 months. I put it back together this week and it worked right away, with the same delay at power-up, followed by the resounding click. It has now quit, again. It seems to me that my success with the receiver following the long period of disuse in these last months might be attributed to a capacitor's gradual discharge. Perhaps some capacitor associated with initial power delivery has stored too great a charge, and it has prevented the flow of power into the unit. It is probably obvious that I have nothing more than a very basic knowledge of electronics; I can handle mecanical work very easily, but electronics repair without guidance is daunting to me. Do you have any suggestions for diagnosis and repair of my ailing SX-780? I really don't trust the tradesmen in my area, and would prefer to try to handle things myself, if this is at all possible. I dearly miss the clear, mellow sound that only a 20+ year old receiver can provide, and hope that it can once more provide reliable service. Thanks for any help you can provide.A: Hello,
Interesting story. Your capacitor theory does not hold water, however, I believe you are on the right track concerning the passage of time. I suspect you have one or more components that are failing after the unit has been powered up for a length of time. They are reaching an operating temperature that causes them to fail. Because they normally would not fail under these conditions, they are known to be 'thermal'. The usual course of diagnosis would be to operate the unit, with all covers on, until it fails. Then quickly remove the cover and spray the components with a cooling agent known as 'freeze spray'. When you spray the bad component, the unit will come back up. This procedure is somewhat tricky and you should always verify your findings with several trials. I would start by testing the components in the power supply section.
Thanks for writing.
Tim
Mr. Whyte,
I am writing to you in regard to a Q&A you answered on 3/25/00 on the Classic Audio website regarding a Pioneer SX-780 receiver that intermittently failed to turn on. The person submitting the question reported that the protection relay was failing to kick in and turn on the outputs. I also own that receiver and several months ago it quit working with exactly the same symptom, but it was a solid failure rather than intermittent. I just found time to look into it recently and managed to find my owners manual and a wiring diagram and started to trace things out. What I found was that I apparently had two cracked solder joints on the D712 transistor. I am not an electrical expert but it appeared that this transistor supplied power to the PA3004 module which in turn energized the relay in question. Re-heating the joints on this transistor seems to have solved the problem.
As the Q&A does not have an e-mail for the individual who originally submitted the question, I was hoping you could pass my experience on to him/her in the hope that it might be of assistance. I would encourage them to inspect the solder joints with a magnifying glass.
Please feel free to pass my e-mail onto this person as well. If they wanted a copy of the wiring diagram or manual I would be happy to make one for them.
Sincerely,
Mark Myers
03-07-00
Q: Hi tim,
Recently I came into a pair of older jensen speakers that had
information on the back regarding ohms.It states they are 16 ohms.I don't
know much about this and was wondering if you could give me an idea of the
difference between these 16 ohms speakers and 8 ohm speakers.Also is there
anything I should know or do before hooking them up ? Most speakers I have
owned up till now have always said 8 ohms on the backs of the speakers.Thanks
for you help and advice.
regards roccoA: Hello Rocco,
Back in the olden' days, amps would have speaker 'taps' of different impedance ratings. The idea being that you connect your speakers to to proper 'tap' based on the rated impedance of the speaker, generally 4, 8, or 16 ohms. These days, most amps are designed to operate with 8 ohm loads. You can connect your 16 ohm speakers with no problem. You will not get the maximum 'power transfer' due to the mis-match in impedances, but you will do no harm. It is possible to cause damage, though, by going the other direction with the impedance. Four ohms should be OK, but less than that and you may have problems. So, always be careful when connecting more than one pair of speakers to an amplifier. Remember, connecting speakers of the same impedance in parallel halves the impedance while connecting them in series doubles it.
Thanks for writing.
Tim
02-22-00
Q: Tim,
I have recently acquired a dbx 1bx noise reduction unit with the
belief it would not only remove hiss from my tape deck, but also remove
scratch and pop from my turntable. It unfortunately came without
instructions and I am hoping you might be familiar with it's general
operation or know where I might locate a manual. Will it help reduce noise
from my turntable or is it exclusively for tape decks? Thanks for any help
you can offer.A: Hello Mark,
The 1BX is what is known as an 'expander'. It is called that because it 'expands' the dynamic range of reproduced music by making the loud parts louder and the soft parts softer. One of the benefits of this process is the reduction of background noise between musical passages. This is especially noticable with magnetic tape and vinyl, but it can work well with radio too. As for vinyl in particular, it will reduce the background or surface noise but will not eliminate or even reduce the 'scratch and pop'. There were, however, devices made that were designed to eliminate transient 'pops' from vinyl. Manufacturers Burwen Research and SAE come to mind.
Thanks for writing.
Tim
02-18-00
Q: Dear Tim,
I have a Beogram 3000 turntable from 1974. About a year ago the belt fell
off. I tried putting it back on, but it kept slipping off. I finally
ordered a new belt, but it's still too loose. I don't know if some part has
gone missing, something else is broken or if I'm just stupid...but I can't
make it work. Do you have any idea what I could be doing wrong? I'd really
appreciate any help. I'm going insane! Kim in VAA: Hello Kim,
Please do not go insane. There are already a lot of people doing that and a lot of them are designing audio equipment! If you did not get the belt from B&O, that might explain the problem, they use a Swedish unit of measurement called the "metric schnitzel". B&O made two versions of the 3000 turntable, the first one had a problem with the motors burning up because they did not work well with the U.S. standard of 60Hz. It may be that you received a belt for the newer model. If you did get the belt from B&O, and they sent you the right one, check the rubber mounts that support the motor.
Thanks for writing.
Tim
Hi,
On your Ask The Tech page I noticed one of your readers had a problem refitting
the belt on a Beogram 3000 turntable. I have had similar problems myself and
found that whilst the belt seems too loose, it's actually ok. The belt slips
off because if the turntable spins whilst the heavy platter is removed (as is
the case when refitting the belt) it's too high. You need to hold down the
spring turntable whilst fitting the belt (not easy) and then carefully replace
the platter without turning anything. Then give it a spin and it should be ok.
It took me while to figure this out, and I nearly gave up. I hope this tip is
of use and maybe you could relay it.
01-09-00
Q: Dear Tim,
I have the opportunity to purchase a Luxman 264 turntable with an MA 3002
cartridge. I am in the market because my turntable recently went bye-bye.
The turntable is in creampuff shape and works well. My problem is that I
know absolutely nothing about the "Luxman" brand and how good their
turntables are considered to be.A visit to the Luxman website looked promising, but it seems that they are
not in the turntable business anymore. The archives of your equipment deals
lists several Luxman components, but nothing about a turntable.I ask the question because I don't want to go into this deal and get taken.
Can I expect to get some more miles from this or is it so old that I may be
in the market for a replacement soon? Did Luxman build a good turntable, or
was it the "Yugo" of its' era? Where does the brand "Luxman" reside on the
electronics foodchain?You don't need to take too much of your time on this, I'd just like your
opinion on a ballpark figure of it's worth so I don't get taken in this
deal.Thanx for your time,
David G.
A: Hello David,
The Luxman brand is highly regarded among audio enthusiasts. In their heyday, they were known as the "Japanese McIntosh". In addition, they made some very fine turntables. I am not personally familiar with the PD-264 model, but I can tell you that it was made between 1976 and 1980 and sold for $300.00. Current value is unknown, my 1994 Blue Book puts it at $14.00 but the Blue Book isn't very reliable these days.
Thanks for writing.
Tim
Click here to read 'Ask The Tech' from 1999.
Copyright-classicaudio.com
