Differences

This shows you the differences between two versions of the page.

--- hotrod [2023/02/15 14:53] – [Rework solder joints] wadmin
+++ hotrod [2023/02/15 16:01] (current) – wadmin
@@ Line 1: / Line 1: @@
 ====== Fender HotRod Bugfix Collection ======
 My tips and tricks collection for tackling Fender HotRod issues - 2023 Edition
+All those tricks have been applied to my personal HotRod with great success, most illustrations comping from this experience.
 {{ ::hotrod:hotrod.png?nolink&600 |}}
@@ Line 116: / Line 118: @@
 Inspect PCB and look for suspicious solder joints as per those detailed here https://meyerems.com/effective-soldering-iron-rework/
-You want to investigate the following components:
+You want to investigate in priority the following components:
 === Critical heating components ===
- * **Low voltage power resistors R78 and R79** can get really hot and their solder joints are stressed a lot. Inspect these first.
+  * **Low voltage power resistors R78 and R79** can get really hot and their solder joints are stressed a lot. Inspect these first.
 {{drawio>hotrod:r78r79.png}}
- * Footswitch circuitry R97 is a good candidate too. Heats a lot.
+  * **Footswitch cricuit R97** is a good candidate too. Heats a lot.
 {{drawio>hotrod:r97.png}}
-on Capacitors (listing),
+  * Inspect all polarisation resistors in PCB, especially R4, R11, R16, R57, R58, R61, R62, and eventually power resistors R74 and R75.
-Strengthen PCB tracks,
+=== Capacitors ===
+  * power capacitors C31, C33, C35, C36, C40, C41 are large capacitors on which vibrations tend to stress solder joints. Inspect and rework them if needed.
+{{drawio>hotrod:C40C41.png}}
 ==== Apply solder paste on weakened tracks ====
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 {{drawio>hotrod:soldertracks.png}}
-//Example of HotRod's 10W PSU resistors with strengthened copper tracks - Source Music Electronics Forum//
+//Example of HotRod's 5W PSU resistors with strengthened copper tracks - Source Music Electronics Forum//
 Simply scratch the varnish over tracks using a sharp knife to reveal raw track copper, clean with alcohol/acetone, and then apply solder paste using iron.
@@ Line 142: / Line 149: @@
 ===== Bugfix #4 - Replacing and strengthening PCB components =====
+The components listed in this section are worth replacing if any damage or sound issue is identified.
+There are some complete replacement kits avaiable on the internet, which include all components that are generally worth upgrading.
 ==== Replace power capacitors ====
-Aging components should be replaced.
+If your main power capacitors are from the IC brand, generally shipped in light grey as shown below, they are low quality chinese capacitors which are prone to leak, seriously reducing amp performance.
+Consider replacing them with same value/voltage rating (FT, etc...).
+{{drawio>hotrod:changecap.png}}
 ==== Replace burnt resistors ====
-Install stronger components for LV power stage.
+Resistors R78 and R79 of the low voltage part are 5W 470 Ohms, but are exposed to transients up to 4.9W (48V@470Ohms). Upgrading these to higher quality 10W wired resistors is encouraged. Notably, installing the resistors slightly above PCB to increase air flow is recommended.
+{{drawio>hotrod:reschange.png}}
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 ===== Bugfix #5 - Glue them all =====
+If not implemented, use RTV glue to fix large components, including all big capacitors.
+{{drawio>hotrod:glue.png}}
+Generally, medium sized capacitors from Power Supply are not glued and I suggest to glue them, because radial capacitors are sensitive to vibrations and this amp is really punchy.
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