Yaesu FT 980 psu cooling mod

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Ashtec
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Yaesu FT 980 psu cooling mod

Post by Ashtec »

I've posted this up just to see what others have done to keep there old yaesu's cool.
And has any one updated the cooling of a FT980
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Ashtec
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Re: Yaesu FT 980 psu cooling mod

Post by Ashtec »

Any one??
electronica special
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Re: Yaesu FT 980 psu cooling mod

Post by electronica special »

yes i have,owned the 980 for 10 years now,even on receive after 20 minutes the psu heat sink is hot & fan kicks in & struggles to keep the radio cool.took the back plate off to expose the heat sink,have attached a small computer fan running at half speed (now silent running) to the psu heat sink,the fan is powered by the radio itself & now the psu stays cold to the touch all day every day !
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Ashtec
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Re: Yaesu FT 980 psu cooling mod

Post by Ashtec »

electronica special wrote:yes i have,owned the 980 for 10 years now,even on receive after 20 minutes the psu heat sink is hot & fan kicks in & struggles to keep the radio cool.took the back plate off to expose the heat sink,have attached a small computer fan running at half speed (now silent running) to the psu heat sink,the fan is powered by the radio itself & now the psu stays cold to the touch all day every day !
I was thinking i was the only one that was concerned about this heat problem from the PSU and the PA of the radio.
To be honest with you ive not used the radio lately so ive not done much about it but my idea was to remove the back plate and remove the old fan unit and retrofit a new back plate with two 12 volt high flow cooling fans fitted to the new Back plate and fit a new thermostat circuit to the radio to run them. ie the fans would run on tick over at low speed all the time unless the radio get's hot then they would cut in to full speed mode to cool the back end down when wormed up.
electronica special
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Re: Yaesu FT 980 psu cooling mod

Post by electronica special »

a great radio & not often seen,an economy version of the expensive hard to sell when new ft1i believe the story goes !
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Re: Yaesu FT 980 psu cooling mod

Post by Hungary »

Szervusztok.nekem is van ft-980.mint mindenkinek gyárilag melegszik a PSU.ennek okka az alul méretezett alkatrészek. a psu-ban található 2 db áteresztő tranzisztor il 2 db egyenirányitó kocka.a 24 voltos rendszer rendben van.vételben 200 ma folyik ralyta mely elenyésző hőt termel.50Amperes tranzisztor il 25Amperes egyenirányitó kocka,bár ezt is érdemes 50Amperosra kicserélni.feleződik a terhelése.a nagyobb gond a 13.5 voltós körben van.alul méretezet alkatrészekkel.ugyan az elmélet azt diktálja elegendő a paraméterek miat.az ft-980 13.5 volton 2.5 A mpert vesz fe.erre egy 5vb10 egyen irányitó kocka van téve.valoban elbirja a kivánt terhelést de 6 amper a max terhelhetősége és a ralyta átfolyó áram folyamatosan 2.5 A mper ami 42% kihasználatság ami folyamatos működés közben oltári hőt termel.DISZIPÁL.adásban 75% kihasználtság ami még megnőveli a DISZIPÁCIÓT.ennek cserélye egy legalább 25 Amperesre de ha nagyobb az se gond /35-50Amperesre/ megoldlya a melegedési problémát.tehát a 5vb10 egyenirányitó okoza a legtöbb hő termelést.még érdemes kicserélni a 2sd717 tranzisztort is mely 10 Amperes határadatal rendelkezik.ezt egy BD249-re megy 25Amperes határadatal rendelkezik s ez is a rajta átfolyó folyamatos 2.5A merten kisebb hőt diszipál mnt az eredeti.ezek cserélye lényegesen csökenti a PSU hűtőborda melegedését melynek köszönhetöen az elkókk 18000uf 25v nehezeben megy tönkre mivel ez van közvetlen a borda melet bár belül de átmelegszik.remélem tudtam hasznos infót adni mindenkinek.erre ez a legjóbb megoldás és nem kell külső hűtőventilátor mivel nehezebben fog melegedni.köszönettel HA7JBG

Hi. I also have ft-980. As everyone is preheating the PSU. The reason is the undersized parts. the 2 transistors in the psu il 2 rectifier cubes. the 24 volt system is OK. 200 m ralyta is running which produces negligible heat.50 amp transistor il 25 amp rectifier cubes, although it is worth replacing it with 50 amps. The biggest problem is with the 13.5 volt circuit. 6 amps is the maximum load capacity and the current flowing continuously is 2.5 amps which is 42% utilization which produces altar heat during continuous operation. / 35-50Amperes / solves the heating problem. So the 5vb10 rectifier causes most of the heat production. It is still worth replacing the 2sd717 transistor which has 10 Amps It has a 25D amp limit on the BD249 and it also dissipates less heat than the original 2.5A because of this. rib heat bar inside but it heats up. i hope i could give useful info to everyone. for this it is the best solution and you don't need an external cooling fan as it will be harder to heat up. thanks HA7JBG
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