perry i have all the components to begin with the repair work,
i was doing some analogies, please tell me wath do you think?,
The Mtx 2300 gives 300 watts x 2 into a 2 Ohm
and my amp gives 150 w *2 @2 ohm
i made this P= V*V/R 300=V*V/2ohms V=24.5 in mtx2300
and it uses 680 ohms resistor in paralell with the out
The power that r=680 ohms consume will be .88 watts
p= 600/680 (mtx 2300x) in case of my amp will be .88=300/r?
R?= 300/.88=340 ohms
conclusion: the half power, the half resistor
i was doing some analogies, please tell me wath do you think?,
The Mtx 2300 gives 300 watts x 2 into a 2 Ohm
and my amp gives 150 w *2 @2 ohm
i made this P= V*V/R 300=V*V/2ohms V=24.5 in mtx2300
and it uses 680 ohms resistor in paralell with the out
The power that r=680 ohms consume will be .88 watts
p= 600/680 (mtx 2300x) in case of my amp will be .88=300/r?
R?= 300/.88=340 ohms
conclusion: the half power, the half resistor
Hi, i have installed the components, and when i try to turn the amp on, it turn on for about 1 second, and then it turns off, all fets are in good condition, i do not know what is happening, my power supply gives 17 Vdc, could this cause the amp protects it self (overvoltage)?, i put a 3 amperes fuse, the amp in rest should consume 1 or 2 amps max (i think, because other amps i have consumes that)
I don't know if MTX has over-voltage protection.
What are the specifications on your power supply (output current and voltage)?
If you can not lower the voltage on your supply, can you locate a regulated power supply to test the amp on?
What test equipment do you have (oscilloscope, multimeter...)?
If you connect a test speaker to the amp, does it make any sound before the amp shuts down (a 'popping' sound may indicate DC offset problem)?
What are the specifications on your power supply (output current and voltage)?
If you can not lower the voltage on your supply, can you locate a regulated power supply to test the amp on?
What test equipment do you have (oscilloscope, multimeter...)?
If you connect a test speaker to the amp, does it make any sound before the amp shuts down (a 'popping' sound may indicate DC offset problem)?
I going to use another power supply at 12 volts
I have a digital multimeter, i have not conected any speaker to the output,but first i giong to use a 12 volts cd power supply, if the amp steal turn off i going to use a speaker an se if i got sound
i was thinking about the lm339 or the tl494 or some bad capacitor
I have a digital multimeter, i have not conected any speaker to the output,but first i giong to use a 12 volts cd power supply, if the amp steal turn off i going to use a speaker an se if i got sound
i was thinking about the lm339 or the tl494 or some bad capacitor
i used a 12 volts power supply and the amp do not turn off, i conected one speaker to one channel and work fine at low volume and the other channel works fine too.
there is only one think that worries me , one of the output fets gets so hot so i turn off the amp, i am afraid i´ll burn that fet,
only this fet gets hot even if there is no speaker conected to that channel
there is only one think that worries me , one of the output fets gets so hot so i turn off the amp, i am afraid i´ll burn that fet,
only this fet gets hot even if there is no speaker conected to that channel
Check the resistors that drive the gates of the FETs in the channel where the FET is getting hot. If the value is more than 5% from what it should be, you need to replace it. You may have to pull one leg of the resistor being tested from the board to get an accurate reading.
If the resistors are OK, turn the bias down a little for that channel. It's unlikely a bias problem because both of the FETs would likely have been overheating but it's something you should try.
If neither of those solve the problem, you could have a defective driver. Finding the defective driver is not too difficult but can be time consuming.
If the resistors are OK, turn the bias down a little for that channel. It's unlikely a bias problem because both of the FETs would likely have been overheating but it's something you should try.
If neither of those solve the problem, you could have a defective driver. Finding the defective driver is not too difficult but can be time consuming.
When servicing the 2300 its very important to replace the complete bank of IRF540's with a Vgs matched set of 4. If Fets have failed in both the pos and negative half a VGS matched set of 8 will be required. When I designed this unit I used very small source degeneration resistors, mainly just for current sensing purposes, so there is almost no source degeneration and at the power dissipation levels involved if each set of 4 fets isnt VGS matched to within 20 mA of of each other under high load the (the lowest VGS threshold fet will grab all the current and blow) unbalance will cause premature failure.
Hi amplifiers inc,
could you tell me the specs for the RTA450 and the RTA2150 ?
I fixed both amps (actually there had only been bad soldier joints and a few old capacitors) . As I have seen a couple of different amplifiers in my life I was impressed that with so many high power parts the power ratings are rather low. Are those amps 1ohm stable ?
Thx
Stephan
could you tell me the specs for the RTA450 and the RTA2150 ?
I fixed both amps (actually there had only been bad soldier joints and a few old capacitors) . As I have seen a couple of different amplifiers in my life I was impressed that with so many high power parts the power ratings are rather low. Are those amps 1ohm stable ?
Thx
Stephan
could you tell me the specs for the RTA450 and the RTA2150 ?
Well first of all there were at least 2 different series of road thunder amplifiers in the 90's. The first series was pre 1994 and they were pretty weak design wise as they were made for MTX by another manufacturer and were essentially just a me too amplifier offering. The second series debuted circa 1998 and were a lot better because they were derived from the original Thunder series of mobile amplifiers designed 94-97. The original Thunder series were packed full of innovations and original engineering tailored to optimize each area of the design from power converter to output stage and the 98 Road Thunder series were more or less clones of these with a reduced feature set such as lower quality power and speaker connectors, lower mass heatsinks, less costly logos etc.
Well first of all there were at least 2 different series of road thunder amplifiers in the 90's. The first series was pre 1994 and they were pretty weak design wise as they were made for MTX by another manufacturer and were essentially just a me too amplifier offering. The second series debuted circa 1998 and were a lot better because they were derived from the original Thunder series of mobile amplifiers designed 94-97. The original Thunder series were packed full of innovations and original engineering tailored to optimize each area of the design from power converter to output stage and the 98 Road Thunder series were more or less clones of these with a reduced feature set such as lower quality power and speaker connectors, lower mass heatsinks, less costly logos etc.
please help again repairing 1502 amp
Hi everybody in the forum again i`m asking for help, i`m repairing again my old mtx pro thunder 1502 and perri babin help me a lot he give a valuo of R from similar amp but some R in parlell shows signs of overheating an began to turn dark i think maybe the value of the R is not the rigth one now i have 680 ohms in R11 and R121(it worked awesome for many years), now i`m asking for help again can someone tell me the exact value of R11 and R121, plese any help will be apreciated, someone who owns this amp please thell me the value of this R`s
Hi everybody in the forum again i`m asking for help, i`m repairing again my old mtx pro thunder 1502 and perri babin help me a lot he give a valuo of R from similar amp but some R in parlell shows signs of overheating an began to turn dark i think maybe the value of the R is not the rigth one now i have 680 ohms in R11 and R121(it worked awesome for many years), now i`m asking for help again can someone tell me the exact value of R11 and R121, plese any help will be apreciated, someone who owns this amp please thell me the value of this R`s
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Hi again
I tried to fix my amp for second time i Burned the outputs irf540 because i got some Speaker wire grounding i bought 8 cheap from aliexpress and díd not worked i thinkk the fets were fake.
Now for third time i Want to repair this amp. I got some fets P33n10 and looking at the data sheet i think i could réplace the irf540 with p33n10. II found some info about p33n10 replaces irf540a, could somebody help me please i do not Know if this is posible, and if it is i do not Know if i must change the gate resistor value. Than so much for yor help
I tried to fix my amp for second time i Burned the outputs irf540 because i got some Speaker wire grounding
i bought 8 cheap from aliexpress and díd not worked i thinkk the fets were fake. Now for third time i Want to repair this amp. I got some fets P33n10 and looking at the data sheet i think i could réplace the irf540 with p33n10. II found some info about p33n10 replaces irf540a, could somebody help me please i do not Know if this is posible, and if it is i do not Know if i must change the gate resistor value. Than so much for yor helpi think as " amplifiers inc " already stated you need to check all the mosfets that you want to install, you cannot simply get for fets and install them. Although they are the same type they differ in their characteristics.
Vishay has a basic procedure to measure VGS
https://www.vishay.com/docs/90715/an957.pdf
You need to find 4 fets that have values as close as possible. Otherwise the parallel bank will run unstable and the weakest fet will have to handle all the current, therefore it will fail first.
Vishay has a basic procedure to measure VGS
https://www.vishay.com/docs/90715/an957.pdf
You need to find 4 fets that have values as close as possible. Otherwise the parallel bank will run unstable and the weakest fet will have to handle all the current, therefore it will fail first.
Hi updating the status the fets irf540 were fake i installed four irf540 used from a psu card and the amp worked fine clear audio, the only problem i have only four 540 i have irf540n but i read some comments from Perry that irf540n has some problems has substitute of 540, so i have some p75nf75 a installed four instead of 8 and worked great, the 75nf75 is 75 volts 80 amp, do you think i could have problems in the future with this config of 4 fets, i left only 4 because the 75 is more than twice the amp capacity i did not want to install 8 because i think the drivier transistors could suffer with the capacitance.
What do you think left only 4 or install the other 4 havin intotal 8 fets p75nf75
Thank you for your comments i wil apreciate them.
What do you think left only 4 or install the other 4 havin intotal 8 fets p75nf75
Thank you for your comments i wil apreciate them.
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